1. science
2. physics

Determination of the Free Neutron Lifetime
J. David Bowman,1 L. J. Broussard,2 S. M. Clayton,2 M. S. Dewey,3 N. Fomin,4 K. B. Grammer,4 G. L. Greene∗ ,4, 1, †
P. R. Huffman,5 A. T. Holley,6 G. L. Jones,7 C.-Y. Liu,8 M. Makela,2 M. P. Mendenhall,3 C. L. Morris,2
J. Mulholland,4 K. M. Nollett,9, 10 R. W. Pattie, Jr.,2 S. Penttil¨a,1 M. Ramsey-Musolf,11 D. J. Salvat,8, 2
A. Saunders,2 S. J. Seestrom,2 W. M. Snow,8 A. Steyerl,12 F. E. Wietfeldt,13 A. R. Young,5 and A. T. Yue3
1
Oak Ridge National Laboratory, Oak Ridge, TN
Los Alamos National Laboratory, Los Alamos, NM
3
National Institute of Standards and Technology, Gaithersburg, MD
4
University of Tennessee, Knoxville, TN
5
North Carolina State University, Raleigh, NC
6
Tennessee Technological University, Cookeville, TN
7
Hamilton College, Clinton, NY
8
Indiana University/CEEM, Bloomington, IN
9
University of South Carolina, Columbia, SC
10
San Diego State University, San Diego, CA
11
University of Massachusetts, Amherst, MA
12
University of Rhode Island, Kingston, RI
13
Tulane University, New Orleans, LA
arXiv:1410.5311v1 [nucl-ex] 20 Oct 2014
2
I.
EXECUTIVE SUMMARY
Neutron beta decay is an archetype for all semileptonic charged-current weak nuclear processes. As a result, an
accurate determination of the parameters that describe neutron decay is critical for the detailed understanding of a
wide variety of nuclear processes. In cosmology, the neutron lifetime determines weak interaction rates and therefore
the helium yield of big bang nucleosynthesis (BBN). The neutron lifetime, along with neutron decay correlations,
nuclear and kaon decay data, can be used to test the unitarity of the CKM matrix and probe physics beyond the
standard model. Such tests are highly complementary to information that is anticipated from the LHC.
Given its importance, it is disturbing that the most accurate determinations of the neutron lifetime are discrepant.
The neutron lifetime has been measured by a decay-in-flight method known as the “beam method” and a neutron
confinement method known as the “bottle method” [1]. While there is consistency among the beam measurements
and among the bottle measurements, the two sets of experiments disagree by ∼8 seconds (out of a lifetime of ∼880 s),
which corresponds to a nearly 4 σ difference. The most likely explanation for this discrepancy is an underestimation
of systematic effects. It is notable that this discrepancy is large enough that it is the dominant uncertainty in the
prediction of the primordial helium/hydrogen abundance ratio.
It is essential to improve the reliability of both beam and bottle measurements of the neutron lifetime, as they
have independent and very different systematic effects. We have outlined a path to achieve this that is affordable, is
technically feasible, and engages a committed community of researchers. A new magneto-gravitational neutron bottle
experiment at LANL (UCNτ ), which eliminates material wall interactions and mitigates other systematic effects, is
capable of achieving an ∼1 second accuracy. At NIST, the latest version of the neutron beam experiment is taking
advantage of a recent advance in the accurate determination of neutron flux and should also provide a measurement
with an uncertainty of ∼1 second. The realization of two systematically independent experiments at the ∼1 second
level will provide a robust determination of the neutron lifetime that is sufficiently accurate for cosmology. This result
should be available in the next 3-4 years.
A measurement with an accuracy of few tenths of a second is required to substantively probe physics beyond the
standard model at an energy scale beyond the reach of the LHC. This will test the unitarity of the CKM matrix at
a level that approaches 10−4 . Important recent technological advances by the US neutron lifetime community have
established a clear technical path toward neutron lifetime measurements with this uncertainty. This is an important
opportunity, and its realization will project the US into a position of clear leadership in this field. This further
work will require modest capital and operational resources. Both of these projects are being carried out by mature
∗
Corresponding Author
address: [email protected]
† Electronic
Cryogenic resonant microwave cavity searches for hidden sector photons
Stephen R. Parker,1, ∗ John G. Hartnett,1, 2 Rhys G. Povey,1, 3 and Michael E. Tobar1
arXiv:1410.5244v1 [hep-ex] 20 Oct 2014
1
School of Physics, The University of Western Australia, Crawley 6009, Australia
2
Institute of Photonics and Advanced Sensing, School of Chemistry
and Physics, University of Adelaide, Adelaide 5005, Australia
3
Department of Physics, University of Chicago, Chicago, IL 60637, USA
The hidden sector photon is a weakly interacting hypothetical particle with sub-eV mass that
kinetically mixes with the photon. We describe a microwave frequency light shining through a wall
experiment where a cryogenic resonant microwave cavity is used to try and detect photons that
have passed through an impenetrable barrier, a process only possible via mixing with hidden sector
photons. For a hidden sector photon mass of 53 µeV we limit the hidden photon kinetic mixing
parameter χ < 1.7 × 10−7 , which is an order of magnitude lower than previous bounds derived
from cavity experiments in the same mass range. In addition, we use the cryogenic detector cavity
to place new limits on the kinetic mixing parameter for hidden sector photons as a form of cold dark
matter.
I.
INTRODUCTION
Several theoretical extensions of the Standard Model
introduce a hidden sector of particles that interact weakly
with normal matter [1, 2]. This interaction takes the
form of spontaneous kinetic mixing between photons and
hidden sector photons [3, 4]. Paraphotons, hidden photons with sub-eV masses [3], are classified as a type of
Weakly Interacting Slim Particle (WISP) [5]. WISPs can
also be formulated as compelling cold dark matter candidates [6, 7]. Indirect experimental detection of paraphotons is intrinsically difficult. The parameter space of
kinetic paraphoton-photon mixing (χ) as a function of
possible paraphoton mass (mγ0 ) is extremely large, with
many experiments and observations required to cover the
relevant photon frequencies, ranging from below 1 Hz up
to the optical regime. While solar observations strongly
constrain hidden sector photon masses corresponding to
higher optical frequencies [8], the microwave region has
yet to be fully explored.
One of the most sensitive laboratory-based tests to
date is the light shining through a wall (LSW) experiment [9–18], whereby photons are generated on one side
of an impenetrable barrier and then photon detection is
attempted on the other side, presumably having crossed
the barrier by mixing with paraphotons. In the microwave domain, mode-matched resonant microwave cavities can be used for the generation and detection of photons (emitter and detector cavity respectively) [19]. The
low electrical losses of microwave cavities enables subphoton regeneration [20] and as such with appropriate
experimental design extremely low levels of microwave
power can be detected. Although other types of microwave cavity hidden photon searches have been developed [21, 22], they have yet to produce measurements
that exceed the sensitivity of current LSW experiments.
In this letter we discuss the design and results of a cryo-
∗
[email protected]
genic LSW experiment and use the same setup to probe
cold dark matter paraphoton / photon coupling.
II.
EXPERIMENT DESIGN
The sensitivity of a LSW microwave cavity experiment
is dictated by [19]
8
PDET
mγ0 c2
= χ4 QDET QEM
|G|2 ,
(1)
PEM
¯hωγ
where PDET and PEM is the level of power in the detecting and emitting cavity respectively, QDET and QEM
are the cavity electrical quality factors, ωγ is the photon
/ cavity resonance frequency and G is a function that
describes the two cavity fields, geometries and relative
positions. Explicitly, G is defined as
Z
Z
exp (ikγ0 |x − y|)
G = kγ2
d3 x
d3 y
4π|x − y|
(2)
VEM
VDET
×AEM (y) · ADET (x) ,
with A representing the normalized spatial component
of the electromagnetic fields for the appropriate resonant
cavity mode. The absolute value of G is calculated as a
function of kγ0 /kγ , the paraphoton/photon wavenumber
ratio. Calculation of Eq. 2 is non-trivial and has previously been explored in detail [16]. In this experiment we
use the TM0,2,0 resonant mode of two cylindrical cavities
that are axially stacked and separated by 10 cm.
Considering Eq. 1, in order to maximize sensitivity to
χ any LSW experiment should aim to minimize background power in the detector cavity and maximize power
in the emitting cavity. The experiment should also use
high Q cavities and optimize G through appropriate cavity alignment and mode selection (using Eq. 2). As such,
we operate the detector cavity cryogenically to reduce the
level of thermal noise radiating from the cavity. Using a
cavity made from niobium will also increase the Q factor as niobium is a type-II superconductor with a critical
arXiv:1410.5182v1 [hep-ex] 20 Oct 2014
Sensitivity for detection of decay of dark matter particle using
ICAL at INO
N. Dash∗1,2 , V. M. Datar†1,2 , and G. Majumder‡3
1
Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085, INDIA
2
Homi Bhabha National Institute, Anushaktinagar, Mumbai - 400094, INDIA
3
Tata Institute of Fundamental Research, Mumbai - 400005, INDIA
October 21, 2014
Abstract
We report on the simulation studies on the possibility of dark matter particle (DMP) decaying into
leptonic modes. While not much is known about the properties of dark matter particles except through
their gravitational effect, it has been recently conjectured that the so called “anomalous Kolar Events”
observed some decades ago may be due to the decay of unstable dark matter particles (M.V.N. Murthy
and G.Rajasekaran, Pramana, 82, 609 (2014)). The aim of this study is to see if this conjecture can be
verified at the proposed Iron Calorimeter (ICAL) detector at INO. We study the possible decay to leptonic
modes which may be seen in this detector with some modifications. For the purposes of simulation we
assume that each channel saturates the decay width for the mass ranging from 1 − 50 GeV/c2 . The aim
is not only to investigate the decay signatures, but also, more generally, to establish lower bounds on the
life time of DMP even if no such decay takes place.
Index terms— India-based Neutrino Observatory, Iron Calorimeter, Kolar Event, Dark Matter Particle,
Life Time.
∗ [email protected]
† [email protected]
‡ [email protected]
1
33 RD I NTERNATIONAL C OSMIC R AY C ONFERENCE , R IO DE JANEIRO 2013
T HE A STROPARTICLE P HYSICS C ONFERENCE
Towards SiPM camera for current and future generations of Cherenkov telescopes
¨
DANIEL M AZIN1 , P RIYADARSHINI BANGALE1 , J ULIAN S ITAREK2 , J UAN C ORTINA2 , DAVID F INK1 , J URGEN
H OSE1 ,
2
1
2
1
1
J OSE M ARIA I LLA , E CKART L ORENZ , M ANEL M ART´I NEZ , U TA M ENZEL , R AZMIK M IRZOYAN , AND M ASAHIRO
T ESHIMA1
1
2
Max-Planck-Institut f¨ur Physik, D-80805 M¨unchen, Germany
Institut de F´ısica d’Altes Energies (IFAE), E-08193 Bellaterra, Spain
arXiv:1410.5070v1 [astro-ph.IM] 19 Oct 2014
[email protected]
Abstract: So far the current ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs) have energy
thresholds in the best case in the range of 30 to 50 GeV (H.E.S.S. II and MAGIC telescopes). Lowest energy
gamma-ray showers produce low light intensity images and cannot be efficiently separated from dominating
images from hadronic background. A cost effective way of improving the telescope performance at lower energies
is to use novel photosensors with superior photon detection efficiency (PDE). Currently the best commercially
available superbialkali photomultipliers (PMTs) have a PDE of about 30-33%, whereas the silicon photomultipliers
(SiPMs, also known as MPPC, GAPD) from some manufacturers show a photon detection efficiency of about 4045%. Using these devices can lower the energy threshold of the instrument and may improve the background
rejection due to intrinsic properties of SiPMs such as a superb single photoelectron resolution. Compared to PMTs,
SiPMs are more compact, fast in response, operate at low voltage, and are insensitive to magnetic fields. SiPMs
can be operated at high background illumination, which would allow to operate the IACT also during partial
moonlight, dusk and dawn, hence increasing the instrument duty cycle. We are testing the SiPMs for Cherenkov
telescopes such as MAGIC and CTA. Here we present an overview of our setup and first measurements, which we
perform in two independent laboratories, in Munich, Germany and in Barcelona, Spain.
Keywords: MAGIC, CTA, Cherenkov telescopes, photodetectors, SiPMs, avalanche photodiodes, cross-talk,
photodetection efficiency
1
Introduction
Many of the current astro-particle physics experiments
exploit detection technique based on detection of optical
or UV light flashes produced by high energy particles in
various processes. For example, ground-based telescopes
can detect fluorescence (e.g. Pierre Auger Observatory,
[1]) or Cherenkov (e.g. the MAGIC telescopes, [2]) light
produced by particles in atmospheric air showers, neutrino
detectors such as IceCube [3] detect Cherenkov light flashes
produced by muons in ice or water. Also some space-based
instruments (e.g. calorimeter in Fermi-LAT [4]) detect high
energy particles and gamma rays by measuring particle
showers produced in the calorimeter.
The energy threshold of the Imaging Atmospheric
Cherenkov Telescopes (IACTs) is determined by the amount
of Cherenkov photons that a telescope can detect above the
level of the fluctuations of the night sky background (NSB)
light. It is essential to achieve low energy threshold in order to be able to observe and study some classes of objects,
such as pulsars which have intrinsically very soft spectra,
or distant active galactic nuclei, in which the higher energy
part of the emission is absorbed by low energy photon fields
on the way to the observer.
So far the current ground-based IACTs have the energy
threshold in the range of 30 to 50 GeV (H.E.S.S. II and the
MAGIC telescopes). The future CTA project [5] is aiming at
obtaining a trigger threshold of few tens of GeV. Moreover,
the images produced by gamma rays with energies close
to the threshold are badly reconstructed, among others
because of scarce light available. This results in very poor
hadron background suppression at those energies. The noise
produced by NSB in a single camera pixel is only weakly
dependent on the mirror area of the telescope because the
flux of NSB photons is isotropic and constant. On the other
hand the amount of detected photons from extended air
showers increases linearly with the area of the mirror dish.
Moreover, for arrays of IACTs increasing the amount of
light detected by individual telescopes will result in more
telescopes detecting a given shower. Having several images
of the same air shower allows one to further improve the
background suppression and reconstruction of the arrival
direction and energy of the incident gamma ray. Thus going
for larger mirror dishes would further decrease the energy
threshold and improve background reduction. However, the
construction of such large telescopes becomes too expensive
and technically challenging.
Another way of improving the sensitivity at lower energies is to use novel photo-sensors with superior quantum efficiency (QE) and superior timing resolution. One
of a promising possibility are the silicon photomultipliers
(SiPMs, [6, 7, 8, 9]). In fact, SiPMs are already used in
a small Cherenkov Telescope, FACT [10]. In comparison
with photomultipliers (PMTs) used in most of the current
IACT experiments SiPMs are comparably fast, operate at
low voltage (a few tens of V), and insensitive to magnetic
fields. In general, they have good photon detection efficiency (PDE), which eventually in future could lower the
energy threshold of the IACTs, and they can be operated
at high background illumination, hence can increase the
instrument duty cycle. So far, the conventional PMTs have
Overview of Non-Liquid Noble Direct Detection Dark
Matter Experiments
arXiv:1410.4960v1 [astro-ph.IM] 18 Oct 2014
J. Cooley
Department of Physics, Southern Methodist University, Dallas, TX 75275, USA
Abstract
In the last few years many advances have been made in the field of dark
matter direct detection. In this article I will review the progress and status of
experiments that employ detection techniques that do not use noble liquids.
First, I will give an introduction to the field of dark matter and discuss the
background challenges that confront all dark matter experiments. I will also
discuss various detection techniques employed by the current generation and
the next generation of dark matter experiments. Finally, I will discuss recent
results and the status of current and future direct detection experiments.
Keywords:
1. Introduction
The revolution in precision cosmology of the last decade has revealed conclusively that about a quarter of our universe consists of dark matter [1, 2].
Despite the abundant evidence for the existence of dark matter, its constituents have eluded detection.
Phenomenology at the intersection of particle physics, cosmology and
astrophysics gives well-motivated candidates for dark matter. Dark matter
candidates naturally arise from theories that explain the radiative stability of
the weak scale. These theories include supersymmetry [3] and the existence of
extra dimensions [4, 5, 6]. Candidates from these theories are representative
of a generic class of weakly interacting massive particles (WIMPs). In the
hot early universe WIMPs would have been in thermal equilibrium. They
would have decoupled as the universe expanded and cooled, leaving behind a
relic abundance of these particles in the universe today. In order to explain
Preprint submitted to Physics of the Dark Universe
October 21, 2014
Tunable Antenna Coupled Intersubbband Teraahertz Deetector
1
2
Nutan Gautam
G
, Jonaathan Kawam
mura2, Nacer Chahat
C
, Boriss Karasik2, Paaolo Focardi2, Samuel Gullkis2,
Loren Pfeiffeer3, and Markk Sherwin1
1
In
nstitute of Teraahertz Science and Technology, UC-Santa B
Barbara, Santaa Barbara, CA, 93106 USA
2
Jet Propulssion Laboratory
y, California In
nstitute of Techhnology, Pasaddena, CA, 911009 USA
3
Departmeent of Electricaal Engineering,, Princeton Unniversity, Princeeton, NJ 085444 USA
A
Abstract— We report on the development
d
of a tunable anten
nna
cou
upled intersub
bband teraherttz (TACIT) deetector based on
GaaAs/AlGaAs two dimensional electron gas. A successful dev
vice
dessign and micro--fabrication pro
ocess have been
n developed wh
hich
6
2
maaintain the high
h mobility (1.1×
×10 cm /V-s att 10K) of a 2DE
EG
chaannel in the prresence of a hiighly conductin
ng backgate. Gate
G
volltage-controlled
d device resista
ance and directt THz sensing has
beeen observed. The
T goal is to op
perate as a nearrly quantum no
oise
lim
mited heterodyn
ne sensor suittable for passiively-cooled space
plaatforms.
I. INTRODUCTION
T
HZ mixers fo
or astronomicaal applications are dominated by
low-noise su
uperconducting
g hot electron bolometers
b
(HE
EB)
operating att liquid Heliu
um temperaturres and Schotttky
dioode mixers wh
hich can operaate at ambientt temperature but
b
sufffer from much
h higher noisee. The latter are the only option
forr planetary missions
m
wherre active cry
yocooling is not
n
possible. The Sch
hottky mixers however
h
are no
ot as low noisee as
HE
EB mixers and
d can hardly bee used beyond 1 THz in view
w of
thee lack of sufficciently powerfful solid-state oscillators. Heere,
wee report on an alternativ
ve tunable antenna
a
coup
pled
inttersubband teraahertz (TACIT
T) [1] detector. The goal of this
t
efffort is to deveelop mixers for
f planetary applications
a
with
w
noise comparablle to supercon
nducting HEBss at temperatu
ures
acccessible to passsively-cooled space platform
ms (>50K), alo
ong
witth a gate bias tunable
t
THz seensing.
The active reg
gion of the TA
ACIT detector is a MBE-gro
own
two-dimensional electron gas (2DEG) conffined in a 40n
nm
GaaAs/AlGaAs quantum
q
well designed for
f
intersubbaand
abssorption near 2.5THz.
2
This active
a
region is a high mobillity
sysstem whose reesistance has strong
s
temperaature dependen
nce
forr temperatures below 77K. The
T active region is sandwich
hed
bettween a Schotttky front gate and
a a buried back
b
gate madee of
a hhighly doped GaAs
G
layer. Th
he front and back gates can tu
une
thee resonant frrequency as well
w
as the strength of the
inttersubband tran
nsition [2]. Also, they couplle the THz sig
gnal
to the active reg
gion via a twin
n-slot antenna.. The source and
a
draain are ohmic contacts
c
to thee 2DEG which sense the chan
nge
in its resistancee. When THz signal falls on the detecttor,
eleectrons are ex
xcited to the next subband
d, leading to an
inccrease in the teemperature of the electron gas. Theoreticallly,
thee 2DEG has beeen approximatted as a hot eleectron bolomettric
sysstem [1] and in
n the presence of a local osccillator signal, the
inttermediate freq
quency (IF) sig
gnal can be sen
nsed between the
souurce and drain
n terminals. Th
he schematic of
o THz detection
andd IF generatio
on inside a TA
ACIT detector is shown in Fig.
F
1(aa), and Fig. 1(b) shows the microscop
pic image off a
fabbricated TACIT
T device.
The impedancce of the TACIIT detector’s active
a
region was
w
callculated by treeating the two-dimensional electron
e
gas as
a a
out to define the structure and to remove the conducting GaAs
layer from the back plane metal region. Ni/AuGe/Ni/Au metal
sequence was used to deposit ohmic metal for the source,
drain, and backgate contacts and was subsequently annealed.
The source and drain metal pads dimension is 396m167m
to minimize the contact resistance. A Ti/Pt metal sequence is
used to deposit back plane metal to define a twin slot antenna
and front Schottky gate on the active region. A silicon nitridesilicon dioxide-silicon nitride dielectric sequence is used to
deposit a 1.2um thick dielectric layer on top of the back plane
metal containing the antenna. A front gate biasing metal pad
and microstrip containing a THz choke filter are deposited
using Ti/Pt/Au on top of the dielectric layer and contact the
front gate metal already defined on the device. The choke
filter prevents coupling THz radiation from the antenna to the
front gate contact pad.
dipole sheet under tthe influence of an oscillaating current
betweenn the front andd the back gattes [1]. A twinn-slot planar
antennaa circuit was ddesigned to proovide an impeddance match
to the T
TACIT device and to couplee THz radiatioon efficiently
from thee gates to the aactive region.
II. RESULTTS
The hheart of the T
TACIT detectoor is a high m
mobility twodimensiional electron gas. A high m
mobility structuure is known
to havve a strong temperature dependent resistance for
temperaatures lower thhan 77K. A 40nnm quantum w
well with high
mobilityy design alongg with a conduucting back gaate layer was
grown aat Princeton U
University. We successfully m
measured the
mobilityy of 3.6×106 ccm2/V-s at 100K with the baack gate but
minimaal processing. The main proocessing challeenge was to
attain hhigh mobility affter completingg the processinng of TACIT
detectorr, which invoolves multiple dry etches and metal
sequencces. We meassured a maxim
mum mobilityy of 1.1×106
cm2/V-ss at 10K afteer complete faabrication process for the
TACIT detector.
Fig. 1 (aa) Schematic of THz detection aand intermediate frequency (IF)
generationn in a TACIT devvice, where 2DEG
G channel is repreesented by blue
color. (b)) Microscopic imaage of a fabricatedd TACIT device depicting source,
drain, anttenna, THz choke filter, front and bback gates. The SE
EM micrograph
of the acti
tive region (the squuare is the front gaate) is shown in thee inset.
The active region, shown in thee inset of Figg. 1, has the
m. Dry plasm
ma etching has been carried
dimensiion of 4m6
We carried out direct detection measurements by mounting
the device on a silicon lens, assembling the device into a
receiver cryostat and illuminated it with a CO2-pumped
molecular gas far-infrared/THz laser. A photosignal was
measured between the source and the drain terminals, while
gate bias was tuned across the front and back gates. As shown
in Fig. 3, for a given fixed THz pump frequency, the
photoresponse is sharply enhanced above a threshold VT. The
value of VT depends strongly on the frequency of the THz
pump. A key result of the study is this demonstration of
voltage-tunable THz detection.
Figure 4 shows dependence of the threshold voltage VT on
THz pump frequency. We define VT as the bias value at which
the response reaches the average of its peak value and value
close to zero applied bias. With increasing pump frequency,
VT decreases approximately linearly. Further detailed
characterization and theory are needed to understand the
dependence of the photoresponse on THz pump frequency and
voltage.
10K
50K
104
103
0.0
0.5
1.0
VTBG(V)
1.5
2.0
We first carried out dc current-voltage measurements on the
fabricated device. Figure 2 shows the device resistance as a
function of gate bias at 10K, and 50K. The device resistance
can be tuned from 10k range down to few hundred ohms.
This suggests that the front and the back gates function in the
expected manner. The change in the device resistance is due to
the change in the sheet charge density of the quantum well.
1.0
Response (a.u.)
0.8
0.6
0.4
1.63THz
1.89THz
2.24THz
2.54THz
2.74THz
3.11THz
T=18K
T=18K
0.8
0.7
0.6
0.5
0.4
0.3
Fig. 2 Source drain resistance of TACIT device as a function of gate bias
applied between front gate and back gate at 10K and 50K.
1.2
Threshold Voltage (VT)
Resistance ()
0.9
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2
Pump Frequency (THz)
Fig. 4 Dependence of threshold voltage VT on Terahertz pump frequency.
III. SUMMARY
We have designed, fabricated, and demonstrated a tunable
antenna coupled intersubband terahertz (TACIT) detector
where THz response can be enhanced by the gate voltage
applied between the front and back gates. For this, we
developed a fabrication and design process to maintain the
high mobility of a 2DEG channel which is the building block
of the TACIT detector. Voltage-tunable THz photoresponse
has been demonstrated for THz pump frequencies between 1.6
and 3.1 THz
REFERENCES
[1]. Sherwin, M. S. et al., Proceedings of Far-IR, Submm and mm Detector
Technology Workshop (Monterey, CA, 2002)
[2]. Williams, J. B. et al., Phys. Rev. Lett. 87, 03740, (2002).
0.2
0.0
-0.2
ACKNOWLEDGEMENTS
-0.4
We would like to thank National Aeronautics and Space Administration for
research funding. This research was done in part at the Jet Propulsion
Laboratory, California Institute of Technology, under a contract with the
National Aeronautics and Space Administration
0.0
0.2
0.4
0.6
0.8
Gate Voltage (V)
1.0
Fig. 3 Tunable response of the TACIT detector has been demonstrated where
the response of the detector can be tuned by tuning voltage bias across the
front and the back gate.
Drilling deep in South Pole Ice
Timo Karg a) and Rolf Nahnhauer
b)
Deutsches Elektronen Synchrotron, DESY
D-15738 Zeuthen, Platanenallee 6
a) [email protected]
b) Corresponding author: [email protected]
Abstract. To detect the tiny flux of ultra-high energy neutrinos from active galactic nuclei or from interactions of highest
energy cosmic rays with the microwave background photons needs target masses of the order of several hundred cubic
kilometers. Clear Antarctic ice has been discussed as a favorable material for hybrid detection of optical, radio and
acoustic signals from ultra-high energy neutrino interactions. To apply these technologies at the adequate scale hundreds
of holes have to be drilled in the ice down to depths of about 2500 m to deploy the corresponding sensors. To do this on
a reasonable time scale is impossible with presently available tools. Remote drilling and deployment schemes have to be
developed to make such a detector design reality. After a short discussion of the status of modern hot water drilling we
present here a design of an autonomous melting probe, tested 50 years ago to reach a depth of about 1000 m in Greenland
ice. A scenario how to build such a probe today with modern technologies is sketched. A first application of such probes
could be the deployment of calibration equipment at any required position in the ice, to study its optical, radio and
acoustic transmission properties.
INTRODUCTION
. Recently the IceCube Neutrino Observatory at the South Pole has
observed the first cosmic neutrinos up to PeV energies opening this way a
new window to study our universe at large distances [1].
IceCube consists out of 86 strings carrying 60 Digital Optical Modules
deployed between 1450 m and 2450 m depth in the Antarctic Ice shield at
the South Pole over a horizontal area of about one square kilometer. The
successful construction of the detector was strongly dependent on the
ability to drill large diameter holes with high speed down to the deep ice
[2 ].
The IceCube drilling station finally allowed drilling a 2500 m deep hole
of 60 cm diameter in less than 48 hours . A 5 MW power station was used
to produce 880 l/min of hot (90°C) water at a pressure of 135 bar. With
this hot-water-drill, 30 trained people were able to drill a maximum of 20
holes per season and to finish the deployment of 86 strings in seven years
The ARA experiment [ 3] under construction at the South Pole near to
IceCube aims to detect even higher energetic cosmogenic neutrinos at
much lower flux levels [4]. For ARA 37 clusters of 6 dry holes, each 16
cm wide and 200 m deep, should be drilled over a surface area of ≈ 100
km2 to contain antennas for the detection of radio signals from neutrino
interactions. The distance between clusters is 2000 m. For that purpose a
transportable hot water drill has been constructed and has successfully
been used in the 2012/2013 Antarctic season.[5]. Two dry holes could be
drilled per day within two 12-hour shifts. But only 80 m of the holes are
drilled in compact ice.
FIGURE 1: A schematic view of a
possible string design and autonomous
deployment
Extending the frequency range of digital noise measurements to the microwave domain
Stephen R. Parker,1, ∗ Eugene N. Ivanov,1 and John G. Hartnett1, 2
arXiv:1410.5238v1 [physics.ins-det] 20 Oct 2014
1
School of Physics, The University of Western Australia, Crawley 6009, Australia
2
Institute of Photonics and Advanced Sensing, School of Chemistry
and Physics, University of Adelaide, Adelaide 5005, Australia
We describe the use of digital phase noise test sets at frequencies well beyond the sampling
rate of their analog-to-digital converters. The technique proposed involves the transfer of phase
fluctuations from an arbitrary high carrier frequency to within the operating frequency range of the
digital instrument. The validity of the proposed technique has been proven via comparison with
conventional methods. Digital noise measurements eliminate the need for calibration and improve
consistency of experimental results. Mechanisms limiting the resolution of spectral measurements
are also discussed.
I.
INTRODUCTION
Over the past two decades the technique of noise measurements has been refined to the point where its spectral
resolution exceeded the standard thermal noise limit [1].
Yet in many practical cases the extreme spectral resolution is not required. Besides, high-resolution phase
noise measurements are time consuming and technically
involved; they also suffer from the residual sensitivity to
amplitude fluctuations of the carrier signal.
Recent years have seen the introduction of digital test
sets that allow fast and reasonably accurate measurements of differential phase fluctuations between two input signals [2, 3]. This is achieved via the coherent demodulation of the input signals. During this process, an
input signal u(t) = U Cos(ωsign t + Φ(t)) is sampled and
its frequency is measured. The digital replica of the input
signal u(tk ) is then multiplied with a synthesized discrete
cosine and sine wave at frequency ωsign . The following
low-pass filtering eliminates the high frequency spectral
components (at 2 ωsign ) leaving only slowly varying terms
x(tk ) = Sin(Φ(tk )) and y(tk ) = Cos(Φ(tk )). The phase of
the input signal is then computed via the inverse trigonometric function: Φ(tk ) = ArcTan(x(tk )/y(tk )). To reduce the excess phase noise associated with the sampling
process, digital test sets feature multi-channel architecture complemented by the cross-correlation signal processing [4, 5].
When applied to the characterization of phase noise
in oscillators, digital test sets simplify the measurement
process by eliminating the need for phase-locking one oscillator to another [6]. Among their advantages is also
immunity to amplitude fluctuations and the ability to
self-calibrate. The main drawback of digital test sets is
the restricted frequency range: the current commercial
instruments operate below 400 MHz [7].
In this paper we describe a technique that enables highresolution phase noise measurements with digital instruments at frequencies well beyond the sampling rate of
their analog-to-digital converters. Microwave amplifiers
∗
[email protected]
are used as test objects to verify the validity of these
digital noise measurements. We show that the results
of digital noise measurements are very much consistent
with those obtained using the conventional analog based
instruments. We also discuss mechanisms limiting the
spectral resolution of noise measurements involving the
use of the digital phase noise test sets.
II.
MEASUREMENT TECHNIQUE
A schematic diagram of the proposed noise measurement system is shown in Fig. 1. Noise fluctuations from
a two port Device Under Test (DUT) are introduced to a
high frequency carrier (SG1), which is then mixed (M1)
with a lower frequency offset (SG2) to create two sidebands. One sideband is removed via filtering (BPF) before the signal is mixed (M2) with the original high frequency carrier (SG1) and filtered again (LPF), leaving
just the low frequency signal and the noise fluctuations
of the DUT. In essence, the circuit transfers the noise
components from one frequency to a different frequency,
as such we refer to the setup as a transposed frequency
noise measurement system.
In the analysis that follows we represent waveforms as
cosine functions, having dropped the sine components to
allow for a clear and concise display for the reader. In
addition, most amplitude coefficients have been set to
unity.
The signal of the high frequency oscillator (SG1) is
modelled as
cos (ω0 t + δφSG1 ),
(1)
where ω0 = 2πf0 represents the oscillator frequency and
δφSG1 are the intrinsic phase fluctuations of the signal
generator. Eq. (1) is then power divided into two paths,
with one arm passing through the DUT where phase fluctuations of the device δφDUT are imprinted on to the
carrier,
cos (ω0 t + δφSG1 + δφDUT + φDUT ),
(2)
where φDUT is the mean (fixed) phase delay in the DUT.
The output of the DUT is then mixed (M1) with an auxiliary carrier from the signal generator SG2 at a lower
Preprint typeset in JINST style - HYPER VERSION
arXiv:1410.5012v1 [physics.ins-det] 18 Oct 2014
The upgrade of the LHCb trigger system
Conor Fitzpatricka , on behalf of the LHCb trigger.
a European
Organisation for Nuclear Research
Geneva, Switzerland
E-mail: [email protected]
A BSTRACT: The LHCb experiment will operate at a luminosity of 2 × 1033 cm−2 s−1 during LHC
Run 3. At this rate the present readout and hardware Level-0 trigger become a limitation, especially
for fully hadronic final states. In order to maintain a high signal efficiency the upgraded LHCb
detector will deploy two novel concepts: a triggerless readout and a full software trigger.
K EYWORDS : Online farms and online filtering; Trigger concepts and systems; Trigger
algorithms; Performance of High Energy Physics Detectors.
Elliptic and triangular flow of heavy flavor in heavy-ion collisions
Marlene Nahrgang,1 J¨org Aichelin,2 Steffen Bass,1 Pol Bernard Gossiaux,2 and Klaus Werner2
arXiv:1410.5396v1 [hep-ph] 20 Oct 2014
1
Department of Physics, Duke University, Durham, North Carolina 27708-0305, USA
2
SUBATECH, UMR 6457, Universit´e de Nantes, Ecole des Mines de Nantes,
IN2P3/CNRS. 4 rue Alfred Kastler, 44307 Nantes cedex 3, France
(Dated: October 21, 2014)
We investigate the elliptic and the triangular flow of heavy mesons in ultrarelativistic heavy-ion
collisions at RHIC and the LHC. The dynamics of heavy quarks is coupled to the locally thermalized
and fluid dynamically evolving quark-gluon plasma. The elliptic flow of D mesons and the centrality
dependence measured at the LHC is well reproduced for purely collisional and bremsstrahlung
interactions. Due to the event-by-event fluctuating initial
conditions from√the EPOS2 model, the D
√
meson triangular flow is predicted to be nonzero at s = 200 GeV and s = 2.76 TeV. We study
the centrality dependence and quantify the contributions stemming from flow of the light bulk event
and the hadronization process. The flow coefficients as response to the initial eccentricities behave
differently for heavy mesons than for light hadrons due to their inertia. Higher-order flow coefficients
of heavy flavor become important in order to quantify the degree of thermalization.
I.
INTRODUCTION
The evolution of hot and dense QCD matter created
in ultrarelativistic heavy-ion collisions is remarkably well
described by fluid dynamics. Over the recent years several studies have successfully described pT -spectra and
collective flow coefficients measured by RHIC and LHC
experiments. Agreement between fluid dynamical calculations and experimental data favors low values for
the ratio of shear viscosity over entropy density in the
range η/s = 0.08 − 0.24 [1–3], which indicates the formation of an almost ideal fluid. This success was supported strongly by the precise measurements of higherorder flow coefficients in the light hadron sector [4–10].
While nowadays the equation of state is well constraint
by lattice QCD calculations [11, 12], the initial conditions
remain a major source of uncertainty in extracting η/s
[1]. Open questions include many aspects ranging from
equilibration times, possible pre-equilibrium dynamics,
initial correlations to the treatment of multiple scatterings. In addition, a possible core-corona separation and
the hadronization process introduces further uncertainties. Consequently, different setups can describe the data
using different optimal combinations of initial conditions
and values of η/s.
The dynamics of heavy quarks is very different from
the light partons forming the bulk of the medium. Heavy
quarks are produced predominantly in the initial hard
scatterings and are not expected to be in equilibrium with
the light partons at the formation time of the quark-gluon
plasma (QGP). At this initial time τ0 of fluid dynamics
there is thus a clear separation between the collective
nature of the bulk and the out-of-equilibrium evolution
of the heavy quarks. Light hadron flow builds up as a
fluid dynamical response to the initial spatial eccentricities mediated by pressure gradients and is mostly sensitive to the flow in the fluid dynamical medium over
the hypersurface at decoupling. In order to transfer this
bulk flow to the heavy quarks a high interaction rate
with the medium constituents is required. Due to the
larger masses of charm and bottom quarks, inertia effects limit the efficiency of each interaction process to
transfer flow. At early times the temperatures are high
and thus the scattering rate of heavy quarks with the
medium constituents is large. The efficiency of the early
times is, however, balanced by the time needed to develop the flow of the bulk matter, which can then be
transformed to the heavy quarks. The experimentally
determined light hadron v2 and the v2 of heavy-flavor
decay electrons or of D mesons are surprisingly similar
[4, 7–9, 13–15]. The final flow of heavy quarks thus results from integration over the whole evolution time. In
addition, heavy-flavor flow receives contributions stemming from energy loss and from the coalescence with light
quarks at hadronization.
In this work we demonstrate that besides the well studied elliptic flow also the triangular flow of D mesons is
nonvanishing. Investigating the centrality dependence of
the flow coefficients we are able to reveal significant differences between the light hadrons, D and B mesons.
For this purpose we couple the Monte-Carlo Boltzmann
propagation of heavy quarks (MC@sHQ) [16, 17] to the
fluid dynamical evolution of the light bulk sector stemming from EPOS2 initial conditions [18, 19]: These are
obtained from a multiple scattering approach combining
pQCD calculations of the hard scattering and GribovRegge theory of the soft, phenomenological part of the
interaction. Multiple scatterings form parton ladders,
which are identified with flux tubes and mapped to the
initial fluid dynamical profiles after identifying and subtracting jet components. In the following a 3 + 1 dimensional ideal fluid dynamical expansion is performed.
Viscosity effects are mimicked by enhancing the initial
flux tube radii. This EPOS2 version has been applied
succesfully to various bulk and jet observables at RHIC
and the LHC in A+A collisions [18, 19]. A recent upgrade, EPOS3, includes a viscous fluid dynamical evolution, based on [20], and has yielded very good agreement
with data from p+p and p+A collisions [21, 22]. We plan
to couple MC@sHQ to EPOS3 in future work.
¯ 0 → (π 0 η (′) , η (′) η (′) ) decays and the effects of next-to-leading order
B
s
contributions in the perturbative QCD approach
Zhen-Jun Xiao1,2∗ and Ya Li1 , Dong-Ting Lin1 , Ying-Ying Fan3 , and Ai-Jun Ma1
arXiv:1410.5274v1 [hep-ph] 20 Oct 2014
1. Department of Physics and Institute of Theoretical Physics,
Nanjing Normal University, Nanjing, Jiangsu 210023, P.R. China
2. Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems,
Nanjing Normal University, Nanjing 210023, P.R. China and
3. College of Physics and Electronic Engineering,
Xinyang Normal University, Xinyang, Henan 464000, P.R. China
(Dated: October 21, 2014)
In this paper, we calculate the branching ratios and CP violating asymmetries of the five
0
¯
Bs → (π 0 η (′) , η (′) η (′) ) decays, by employing the perturbative QCD (pQCD) factorization
approach and with the inclusion of all currently known next-to-leading order (NLO) contributions. We find that (a) the NLO contributions can provide about 100% enhancements to
¯s0 → ηη ′ and η ′ η ′ decays, but result in
the LO pQCD predictions for the decay rates of B
¯s → π 0 η (′) ) and Br(B
¯s → ηη); (b) the newly known NLO twist-2
small changes to Br(B
and twist-3 contributions to the relevant form factors can provide about 10% enhancements
¯s → π 0 η (′) decays, their direct CPto the decay rates of the considered decays; (c) for B
dir
violating asymmetries Af could be enhanced significantly by the inclusion of the NLO
¯s → ηη (′) ) and Br(B
¯s → η ′ η ′ ) can
contributions; and (d) the pQCD predictions for Br(B
be as large as 4 × 10−5 , which may be measurable at LHCb or the forthcoming super-B
experiments.
I.
INTRODUCTION
As is well-known, the studies for the mixing and decays of Bs meson play an important
role in testing the standard model (SM) and in searching for the new physics beyond the SM
[1, 2]. Some Bs meson decays, such as the leptonic decay Bs0 → µ+ µ− and the hadronic decays
Bs0 → (J/Ψφ, φφ, Kπ, KK, etc), have been measured recently by the LHCb, ATLAS and CMS
collaborations [3–5].
¯ 0 → (Kπ, KK) decays by employing the pQCD
In a very recent paper [6], we studied the B
s
factorization approach with the inclusion of the NLO contributions [7–13] and found that the
NLO contributions can interfere with the leading order (LO) part constructively or destructively
for different decay modes, and can improve the agreement between the SM predictions and the
measured values for the considered decay modes [6]. The charmless hadronic two-body decays
of Bs meson, in fact, have been studied intensively by many authors by using rather different
theoretical methods: such as the generalized factorization [14, 15], the QCD factorization (QCDF)
approach [16–18] and the pQCD factorization approach at the LO or partial NLO level [8, 19–
22]. In Refs.[7, 9, 10, 13], the authors proved that the NLO contributions can play a key role in
∗
[email protected]
Double parton interactions in γp, γA collisions in the direct photon kinematics.
B. Blok1 , M. Strikman2
1
Department of Physics, Technion – Israel Institute of Technology, Haifa, Israel
2
Physics Department, Penn State University, University Park, PA, USA
We derive expressions for the differential distributions and the total cross section of double-
arXiv:1410.5064v1 [hep-ph] 19 Oct 2014
parton interaction in direct photon interaction with proton and nuclei. We demonstrate
that in this case the cross section is more directly related to the nucleon generalized parton
distribution than in the case of double parton interactions in the proton - proton collisions.
We focus on the production of two dijets each containing charm (anticharm) quarks and
carrying x1 , x2 > 0.2 fractions of the photon momentum. Numerical results are presented
for the case of γp collisions at LHeC, HERA and in the ultraperipheral AA and pA collisions
at the LHC. We find that the events of this kind would be abundantly produced at the
√
LHeC. For s = 1.3 TeV the expected rate is 2 · 108 events for the luminosity 1034 cm−2 s−1 ,
the running time of 106 s and the transverse cutoff of pt > 5 GeV. This would make it
feasible to use these processes for the model independent determination of two parton GPDs
in nucleon and in nuclei. For HERA the total accumulated number of the events is also high,
but efficiency of the detection of charm seems too low to study the process. We also find
that a significant number of such double parton interactions should be produced in p − P b
and P b − P b collisions at the LHC: ∼ 6 · 104 for P b − P b, and ∼ 7 · 103 for p − P b collisions
for the same transverse momentum cutoff.
PACS numbers: 12.38.-t, 13.85.-t, 13.85.Dz, 14.80.Bn
Keywords: pQCD, jets, multiparton interactions (MPI), LHC, TEVATRON
Nuclear
Physics B
Proceedings
Supplement
Nuclear Physics B Proceedings Supplement 00 (2014) 1–7
arXiv:1410.5045v1 [hep-ph] 19 Oct 2014
Dark energy, QCD axion, BICEP2, and trans-Planckian decay
constant ✩
Jihn E. Kim
Department of Physics, Kyung Hee University, Seoul 130-701, Korea
Abstract
Discrete symmetries allowed in string compactification are the mother of all global symmetries which are broken at some level. We
discuss the resulting pseudo-Goldstone bosons, in particular the QCD axion and a temporary cosmological constant, and inflatons.
We also comment on some implications of the recent BICEP2 data.
Keywords: Discrete symmetry, QCD axion, Dark energy, Inflation
1. Discrete symmetries
singlets at the grand unification (GUT) scale. Can these
singlets explain both DE and CDM in the Universe? Because the axion decay constant fa can be in the intermediate scale, axions can live up to now (ma < 24 eV) and
constitute DM of the Universe. In this year of a GUT
scale VEV, can these also explain the inflation finish?
For pseudo-Goldstone bosons like axion, we introduce global symmetries. But global symmetries are
known to be broken by the quantum gravity effects, especially via the Planck scale wormholes. To resolve
this dilemma, we can think of two possibilities of dis-
The cosmic energy pie is composed of 68% dark
energy (DE), 27% cold dark matter (CDM), and 5%
atoms [1]. Among these, some of DE and CDM can
be bosonic coherent motions (BCMs) [2]. The ongoing
search of the QCD axion is based on the BCM. Being a
pseudo-Goldstone boson, the QCD axion can be a composite one [3], but after the discovery of the fundamental Brout-Englert-Higgs (BEH) boson, the possibility of
the QCD axion being fundamental gained much more
weight. The ongoing axion search experiment is based
on the resonance enhancement of the oscillating E-field
following the axion vacuum oscillation as depicted in
Fig. 1. It may be possible to detect the CDM axion
even its contribution to CDM is only 10% [4].
The BEH boson is fundamental. The QCD axion
may be fundamental. The inflaton may be fundamental. These bosons with canonical dimension 1 can affect more importantly to low energy physics compared
to those of spin- 21 fermions of the canonical dimension
3
2 . This leads to a BEH portal to the high energy scale
to the axion scale or even to the standard model (SM)
•
•
•
•
•
•
•
B
•
Ea
hail
✩ This
work is supported by the NRF grant funded by the Korean
Government (MEST) (No. 2005-0093841).
Email address: [email protected] (Jihn E. Kim)
Figure 1. The resonant detection idea of the QCD axion. The E-field
follows the axion vacuum oscillation.
1
B → K1 π(K) decays in the perturbative QCD approach
Zhi-Qing Zhang1 , Zhi-Wei Hou1 , Yueling Yang2 , Junfeng Sun2
arXiv:1410.5026v1 [hep-ph] 19 Oct 2014
1
Department of Physics, Henan University of Technology,
Zhengzhou, Henan 450001, China;
2 College of Physics and Information Engineering,
Henan Normal University, Xinxiang 453007, China
(Dated: October 21, 2014)
Abstract
Within the framework of the perturbative QCD approach, we study the two-body charmless
¯0 →
decays B → K1 (1270)(K1 (1400))π(K). We find the following results: (i) The decays B
K1 (1270)+ π − , K1 (1400)+ π − are incompatible with the present experimental data. There exists a
¯ 0 → a1 (1260)+ K − , b1 (1235)+ K − , which are usually considered
similar situation for the decays B
that the nonperturbative contributions are needed to explain the data. But the difference is that
the nonperturbative contributions seem to play opposite roles in these two groups of decays.(ii)
¯ 0 → K ± (1270)K ∓ , K ± (1400)K ∓ are good channels to test
The pure annihilation type decays B
1
1
whether an approach can be used to calculate correctly the strength of the penguin-annihilation
amplitudes. Their branching ratios are predicted at 10−7 order, which are larger than the
QCDF results. (iii) The dependence of the direct CP-violating asymmetries of these decays on
the mixing angle θK1 are also considered.
PACS numbers: 13.25.Hw, 12.38.Bx, 14.40.Nd
1
Sparticle Mass Hierarchies, Simplified Models from SUGRA Unification, and
Benchmarks for LHC Run-II SUSY Searches
David Francescone,1, ∗ Sujeet Akula,2, 3, † Baris Altunkaynak,4, ‡ and Pran Nath1, §
1
Department of Physics, Northeastern University, Boston, MA 02115, USA
MTA-DE Particle Physics Research Group, University of Debrecen, H-4010 Debrecen P.O. Box 105, Hungary
3
ARC Centre of Excellence for Particle Physics at the Terascale,
School of Physics, Monash University, Melbourne VIC 3800, Australia
4
Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA
2
arXiv:1410.4999v1 [hep-ph] 18 Oct 2014
Sparticle mass hierarchies contain significant information regarding the origin and nature of supersymmetry breaking. The hierarchical patterns are severely constrained by electroweak symmetry
breaking as well as by the astrophysical and particle physics data. They are further constrained by
the Higgs boson mass measurement. The sparticle mass hierarchies can be used to generate simplified models consistent with the high scale models. In this work we consider supergravity models with
universal boundary conditions for soft parameters at the unification scale as well as supergravity
models with nonuniversalities and delineate the list of sparticle mass hierarchies for the five lightest
sparticles. Simplified models can be obtained by a truncation of these, retaining a smaller set of
lightest particles. The mass hierarchies and their truncated versions enlarge significantly the list of
simplified models currently being used in the literature. Benchmarks for a variety of supergravity
unified models appropriate for SUSY searches at future colliders are also presented. The signature
analysis of two benchmark models has been carried out and a discussion of the searches needed
for their discovery at LHC RUN-II is given. An analysis of the spin independent neutralino-proton
cross section exhibiting the Higgs boson mass dependence and the hierarchical patterns is also carried out. It is seen that a knowledge of the spin independent neutralino-proton cross section and
the neutralino mass will narrow down the list of the allowed sparticle mass hierarchies. Thus dark
matter experiments along with analyses for the LHC Run-II will provide strong clues to the nature
of symmetry breaking at the unification scale.
∗
†
‡
§
Email:
Email:
Email:
Email:
[email protected]
[email protected]
[email protected]
[email protected]
2
I.
INTRODUCTION
The discovery [1, 2] of the Higgs boson [3–5] and the measurement of its mass at ∼ 126 GeV have strong implications
for discovery of supersymmetry. In supersymmetry one identifies the observed Higgs boson as the lightest CP -even
state h0 (see e.g., [6–13]). It is noteworthy that the observed Higgs boson mass lies below but close to the upper
limit on the Higgs boson mass predicted in supergravity grand unified models [14–17] with radiative breaking of the
electroweak symmetry (for a review see[18]), and this upper limit is well known to be around 130 GeV [6–13, 19, 20].
Further, in supersymmetric models and specifically those within supergravity grand unification, one finds that a Higgs
mass of ∼ 126 GeV implies the scale of supersymmetry to be large with the squark masses typically lying in the few
TeV region [6–13, 19–21]. The largeness of the SUSY scale explains √
the non-observation of sparticles in searches in
Run-I of the LHC. However, the LHC energy is being ramped up to s = 13 TeV and one expects some of the light
1
sparticles to show up in Run-II .
The nature of the observed sparticles, and more generally the hierarchical mass patterns, hold a key to the nature of
symmetry breaking at high scales in unified models. Given that there are 31 additional particles beyond the spectrum
of the Standard Model, there are a priori 31! ∼ 8 × 1033 ways in which these particles can arrange themselves. This is
the landscape of possible mass hierarchies of the new particles2,3 . The number of allowed possibilities is significantly
reduced in supergravity grand unification with radiative breaking of the electroweak symmetry[23–25]. Additionally,
the accelerator and dark matter constraints further reduce the allowed number of possibilities. The landscape of
supergravity based models was analyzed in a number of works [23–30] which, however, were all before the discovery
of the Higgs boson and a measurement of its mass.
Regarding the Higgs boson mass of 126 GeV, there are a limited number of ways in which one can lift its tree mass
which lies below MZ to the observed value. These include D-term contributions from extra U(1)’s, loop contributions
from extra matter [31] or large loop corrections from within the MSSM. The latter possibility implies a relatively high
scale of supersymmetry, which explains in part the reason for its non-observation thus far. In this work, we revisit
the sparticle landscape analysis taking into account the constraint from the Higgs boson mass measurement on the
sparticle landscape. We analyze several different classes of high scale models: these include mSUGRA (also called
CMSSM) and supergravity models with nonuniversal boundary conditions at the grand unification scale which include
nonuniversalities in the SU(2)L and SU(3)C gaugino sector, in the Higgs sector and in the third generation sfermion
sector. The most dominant hierarchical patterns that emerge are identified. The hierarchical patterns provide a
simple way to connect the simplified models [32–39] with grand unified models. Specifically, we consider five particle
mass hierarchies where the various combinations of the five lightest particles that originate in supergravity models
are investigated. These five particle mass hierarchies effectively constitute existing and novel simplified models. The
hierarchy of five particles can be further truncated to give simplified models with three or four lightest particles as
has been more common. It should be noted that these simplified models are obviously part of a UV complete theory
since they are obtained by truncation of the spectrum arising from a high scale model.
The outline of the rest of the paper is as follows: In section II we give details of the analysis and a cartography
of the allowed 5 particle mass hierarchies including the LSP. Five different classes of high scale boundary conditions
are analyzed. In section III we connect simplified models to the sparticle mass hierarchies. In section IV we discuss
the generic signatures that one expects for the mass patterns. In section V we give benchmarks for future searches
for supersymmetry at colliders. We also give a signature analysis of two benchmark models with a discussion of cuts
needed for their discovery at the LHC Run-II. In section VI we carry out an analysis of spin independent neutralinoproton cross section in terms of the sparticle mass patterns to see how a measurement of the spin independent cross
section along with a knowledge of the neutralino mass can narrow down the possible hierarchical patterns. Conclusions
are given in section VII.
1
2
3
√
√
Although the current plan is for the LHC to operate at s = 13 TeV for Run-II, we will carry out the analysis at s = 14 TeV, using
the Snowmass [22] Standard Model backgrounds.
We would loosely call these the sparticle mass hierarchies even though they contain the Higgs boson states, H 0 , A0 , H ± , which are R
parity even.
The landscape is even larger in that the mass gaps among the sparticles can vary continuously which makes the allowed sparticle
landscape larger than even the string landscape which has as many as 10500 possible vacua.
EFI-14-37
CMS kinematic edge from s-bottoms
arXiv:1410.4998v1 [hep-ph] 18 Oct 2014
Peisi Huanga,c and Carlos E.M. Wagnera,b,c
a
Enrico Fermi Institute & b Kavli Institute for Cosmological Physics,
University of Chicago, Chicago, IL 60637
c
HEP Division, Argonne National Laboratory, 9700 Cass Ave., Argonne, IL 60439
We present two scenarios in the Minimal Supersymmetric Extension of the Standard Model (MSSM) that can lead to an explanation of the excess in the invariant
mass distribution of two opposite charged, same flavor leptons, and the corresponding edge at an energy of about 78 GeV, recently reported by the CMS collaboration.
In both scenarios, s-bottoms are pair produced, and decay to neutralinos and a b-jet.
The heavier neutralinos further decay to a pair of leptons and the lightest neutralino
through on-shell s-leptons or off-shell neutral gauge bosons. These scenarios are
consistent with the current limits on the s-bottoms, neutralinos, and s-leptons. Assuming that the lightest neutralino is stable we discuss the predicted relic density as
well as the implications for Dark Matter direct detection. We show that consistency
between the predicted and the measured value of the muon anomalous magnetic moment may be obtained in both scenarios. Finally, we define the signatures of these
models that may be tested at the 13 TeV run of the LHC.
2
I.
INTRODUCTION
After the Higgs discovery [1, 2], the main goal of the LHC experiments is the search for
new physics at the TeV scale. Current searches at the 8 TeV LHC have provided no evidence
of new physics beyond the Standard Model (SM). There are, however, some intriguing
signatures that may hint to the presence of new physics. For instance, in a recent analysis
of the invariant mass distribution of two opposite charged, same flavor (SFOS) leptons [3],
CMS has reported an intriguing excess of events with respect to the ones expected in the
SM. In this search CMS looks for two isolated lepton final states using the 8 TeV data set
with an integrated luminosity of 19.4 fb−1 . Events with SFOS leptons are selected (e+ e−
or µ+ µ− ) with both leptons having transverse momentum pT > 20 GeV and pseudorapidity
|η|< 2.4. CMS set additional requirements on jets and missing energy, and selects events with
a number of jets Njets ≥2 and missing transverse energy ETmiss > 150 GeV or Njets ≥3 and
ETmiss >100 GeV. The jets are required to have pT > 40 GeV and |η|< 3.0. The selected events
are separated into a central signal region, where both leptons satisfy |η|< 1.4, and a forward
region, where at least one lepton satisfies 1.6 < |η|< 2.4. Then CMS performs a search
for an edge in the invariant mass (mll ) distributions by fitting the signal and background
hypothesis to data in the range of 20 GeV < mll < 300 GeV. The best fit to the SFOS event
distribution is obtained for an edge at an energy of 78.7± 1.4 GeV. An alternative search
is done by a counting experiment, without any assumption of the signal and background
shape. The counting experiment is performed in the mass range of 20 < mll < 70 GeV, and
an excess of 130+48
−49 events are seen in the central region, corresponding to a local significance
of 2.6 σ.
In this article, we shall interpret the presence of this edge as a signature of the production
of third generation supersymmetric particles at the LHC 1 . Supersymmetry is an attractive
framework [5–7], that leads to the unification of couplings at high scales and provides Dark
Matter candidates in terms of the superpartners of the neutral Higgs and gauge bosons.
Moreover, for supersymmetric particle masses of the order of the TeV scale, low energy
supersymmetry leads to the radiative breaking of the electroweak symmetry with a light,
1
During the completion of this work, an alternative explanation of this kinematic edge in terms of first and
second generation s-quarks together with light s-leptons was presented [4].
EFI-14-36, FERMILAB-PUB-14-392-T, MCTP-14-37, SCIPP 14/16
Complementarity Between Non-Standard Higgs Searches and
Precision Higgs Measurements in the MSSM
arXiv:1410.4969v1 [hep-ph] 18 Oct 2014
Marcela Carena a,b,c , Howard E. Haber d,e , Ian Low f,g ,
Nausheen R. Shah h , and Carlos E. M. Wagner b,c,f
a
Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510
b
c
d
e
Enrico Fermi Institute, University of Chicago, Chicago, IL 60637
Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637
Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064
Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 9472
f
g
h
High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439
Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, MI 48109
Abstract
Precision measurements of the Higgs boson properties at the LHC provide relevant constraints
on possible weak-scale extensions of the Standard Model (SM). In the context of the Minimal Supersymmetric Standard Model (MSSM) these constraints seem to suggest that all the additional,
non-SM-like Higgs bosons should be heavy, with masses larger than about 400 GeV. This article
shows that such results do not hold when the theory approaches the conditions for “alignment
independent of decoupling”, where the lightest CP-even Higgs boson has SM-like tree-level couplings to fermions and gauge bosons, independently of the non-standard Higgs boson masses. The
combination of current bounds from direct Higgs boson searches at the LHC, along with the alignment conditions, have a significant impact on the allowed MSSM parameter space yielding light
additional Higgs bosons. In particular, after ensuring the correct mass for the lightest CP-even
Higgs boson, we find that precision measurements and direct searches are complementary, and may
soon be able to probe the region of non-SM-like Higgs boson with masses below the top quark pair
mass threshold of 350 GeV and low to moderate values of tan β.
1
FTUV-14-3008 IFIC/14-57 KA-TP-25-2014 LPN14-109 SFB/CPP-14-66
QCD radiation in W H and W Z production and anomalous coupling measurements
Francisco Campanario,1, ∗ Robin Roth,2, † and Dieter Zeppenfeld2, ‡
1
Theory Division, IFIC, University of Valencia-CSIC, E-46980 Paterna, Valencia, Spain.
2
Institute for Theoretical Physics, KIT, 76128 Karlsruhe, Germany.
We study QCD radiation for the W H and W Z production processes at the LHC. We identify
the regions sensitive to anomalous couplings, by considering jet observables, computed at NLO
QCD with the use of the Monte Carlo program VBFNLO. Based on these observations, we propose
the use of a dynamical jet veto. The dynamical jet veto avoids the problem of large logarithms
depending on the veto scale, hence, providing more reliable predictions and simultaneously increasing
the sensitivity to anomalous coupling searches, especially in the W Z production process.
arXiv:1410.4840v1 [hep-ph] 17 Oct 2014
PACS numbers: 12.38.Bx, 13.85.-t, 14.70.-e, 14.70.Bn
I.
INTRODUCTION
Higgs production in association with a W boson is one
of the main Higgs boson production mechanisms at the
LHC. The LHC experiments did not yet observe the Higgs
boson in this channel, but measurements are compatible
with the Standard Model (SM) prediction [1, 2].
V H production is the best channel to measure the Higgs
decay to b¯b at the LHC since the leptons from the V decay
can be used for triggering and to reduce the backgrounds.
Additionally, it allows the study of the V V H vertex and
possible modifications to it by new physics entering via
anomalous couplings (AC). In this article, we will focus
on W H production.
From the theoretical point of view, W H production
has been extensively studied in the literature and results
at the next-next-to-leading order (NNLO) in QCD have
been provided in Ref. [3] at the total cross section level
and in Ref. [4] for differential distributions. AC effects
are also a subject of interest [5].
Due to the large gluon luminosity, the fraction of W H
events with additional jets is large. Results for W Hj
production at NLO are thus necessary, when one looks at
one jet inclusive events as done by ATLAS [2]. Results
for this process at NLO QCD have been reported both for
W on-shell production [6] and also including the leptonic
decays of the W [7].
In vector boson pair production processes, it is known
that additional jet radiation reduces the sensitivity to AC
measurements, results that have been confirmed at NLO
in Refs. [8, 9]. To reduce this effect and the sensitivity to
higher QCD corrections, the traditional method has been
to apply a jet veto above a fixed pT [10], which comes
with a naive reduction of scale dependence at the total
cross section level. A closer look at the scale uncertainties
in differential distributions reveals that exclusive samples
inherit large scale uncertainties in the tails of the distributions, which are the regions most sensitive to AC
∗
†
‡
[email protected]
[email protected]
[email protected]
effects. This has also been confirmed using merged samples for W W (W Z) and W W j(W Zj) using the LOOPSIM
method [11, 12]. Thus, more sophisticated strategies in
current Monte-Carlo driven analysis are needed to gain
theoretical control.
In this paper, we study the jet radiation patterns at
NLO QCD in W H and W Z production. We will show
that they have distinctive signatures and we will present
a possible strategy to increase the sensitivity in those
channels to AC searches. The constructed jet observables
are shown at NLO QCD. To accomplish this, we have
computed W H(j) production at NLO QCD, including
Higgs and leptonic W decays, and with the possibility
to switch on AC effects. These processes are available in
VBFNLO [13], a parton level Monte Carlo program which
allows the definition of general acceptance cuts and distributions.
The paper is organized as follows. In Section II, the
details of our calculation are given. Numerical results,
including new strategies to enhance the sensitivity to AC
searches will be given in Section III. Finally, in Section IV,
we present our conclusions.
II.
CALCULATIONAL SETUP
The W Z/W Zj samples at NLO QCD are obtained
from Refs. [14, 15] available in the VBFNLO package [13].
The NLO QCD corrections to W Z production were first
calculated in Ref. [16]. To compute the W H(j) production processes at NLO QCD, we simplified the calculation
for lνl γγj [17] production (from now on called W γγj for
simplicity) as explained below. For more details on the
implementation and the checks performed, we refer the
reader to Ref. [18]. There, also, comparisons to earlier
calculations of NLO QCD corrections to W Hj production [6, 7] are discussed. In the following, we sketch some
details of our approach to make this work self-contained.
To compute the LO, virtual and real corrections, we
use the effective current approach and the spinor-helicity
amplitude method [19, 20] factorizing the leptonic tensor
containing the EW information of the system from the
QCD amplitude. This allows us to obtain the code for
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)
CERN-PH-EP-2014-231
arXiv:1410.5404v1 [hep-ex] 20 Oct 2014
Submitted to: Eur. Phys. J. C
Search for invisible particles produced in association
with
√
single-top-quarks in proton-proton collisions at s = 8 TeV
with the ATLAS detector
The ATLAS Collaboration
Abstract
A search for the production of single-top-quarks in association with missing energy is performed
√
in proton–proton collisions at a centre-of-mass energy of s = 8 TeV with the ATLAS experiment
at the Large Hadron Collider using data collected in 2012, corresponding to an integrated luminosity
of 20.3 fb−1 . In this search, the W boson from the top quark is required to decay into an electron
or a muon and a neutrino. No deviation from the Standard Model prediction is observed, and upper
limits are set on the production cross-section for resonant and non-resonant production of an invisible
exotic state in association with a right-handed top quark. In the case of resonant production, for a
spin-0 resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at
95% confidence level for the top quark and an invisible spin-1/2 state with mass between 0 GeV and
100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded
at 95% confidence level for the top quark and an invisible spin-1 state with mass between 0 GeV and
657 GeV.
Keywords ATLAS - LHC - proton–proton collisions - top quark - single-top-quark - monotop
c 2014 CERN for the benefit of the ATLAS Collaboration.
Reproduction of this article or parts of it is allowed as specified in the CC-BY-3.0 license.
Nuclear Physics B
Proceedings
Supplement
Nuclear Physics B Proceedings Supplement 00 (2014) 1–7
¯
Status and Perspectives for PANDA
at FAIR
¯
Elisabetta Prencipe, on behalf of the PANDA
Collaboration
arXiv:1410.5201v1 [hep-ex] 20 Oct 2014
Forschungszentrum J¨ulich, Leo Brandt Strasse, 52428 J¨ulich, Germany
Abstract
The Facility for Antiproton and Ion Research (FAIR) is an international accelerator facility which will use antiprotons and ions to perform research in the fields of nuclear, hadron and particle physics, atomic and anti-matter physics,
high density plasma physics and applications in condensed matter physics, biology and the bio-medical sciences. It is
located at Darmstadt (Germany) and it is under construction. Among all projects in development at FAIR in this mo¯
ment, this report focuses on the PANDA
experiment (antiProton ANnihilation at DArmstadt). Some topics from the
¯
¯
Charm and Charmonium physics program of the PANDA
experiment will be highlighted, where PANDA
is expected
to provide first measurements and original contributions, such as the measurement of the width of very narrow states
and the measurements of high spin particles, nowaday undetected. The technique to measure the width of these very
narrow states will be presented, and a general overview of the machine is provided.
¯
Keywords: DS , Charm, Spectroscopy, confinement, PANDA
1. Introduction
The Standard Model of particle physics is well defined and efficient in describing fundamental interactions. However several questions still remain open. For
example, the theory describing strong interactions, the
Quantum Chromodynamcs (QCD), is still affected by
some unsolved fundamental questions, arising in the
low energy domain, such as the understanding of confinement and the origin of hadron masses. As a nonAbelian theory, QCD allows the self-interaction of the
strong force carriers, e.g. the gluons. In the low enery regime their interactions can only be described exploiting non-perturbative methods. The answer to these
questions is a challenge that requires a new generation
machine and experiments with higher resolution and
better precision, compared to the past.
¯
The future experiment PANDA
will be located at the
HESR at FAIR[1] (High Energy Storage Ring at the Facility for Antiproton and Ion Research), in Germany.
Email address: [email protected] (on behalf of the
¯
PANDA
Collaboration)
In this report we will put emphasis on the description
¯
of the PANDA
experiment, in particular on the detector design and the physics program, to motivate the big
effort in terms of hardware and software that an international collaboration of 18 countries and more than 500
people are presently going through.
2. The physics case
¯
The program of the PANDA
experiment is wide and
ambitious, and covers several areas of interest in nuclear
and particle physics[2].
We plan to study with accuracy the mechanism responsible for phenomena like the quark confinement,
through the investigation of:
• Hadron spectroscopy:
− search for gluonic excitations;
− charmonium spectroscopy;
− D meson spectroscopy;
− baryon spectroscopy;
− QCD dynamics.
arXiv:1410.4909v1 [hep-ex] 18 Oct 2014
Updated Measurement of the Single Top Quark Production Cross Section
√ and |Vtb | in
the Missing Transverse Energy Plus Jets Topology in pp¯ Collisions at s = 1.96 TeV
T. Aaltonen,21 S. Ameriojj ,39 D. Amidei,31 A. Anastassovv ,15 A. Annovi,17 J. Antos,12 G. Apollinari,15
J.A. Appel,15 T. Arisawa,52 A. Artikov,13 J. Asaadi,47 W. Ashmanskas,15 B. Auerbach,2 A. Aurisano,47 F. Azfar,38
W. Badgett,15 T. Bae,25 A. Barbaro-Galtieri,26 V.E. Barnes,43 B.A. Barnett,23 P. Barriall ,41 P. Bartos,12
M. Baucejj ,39 F. Bedeschi,41 S. Behari,15 G. Bellettinikk ,41 J. Bellinger,54 D. Benjamin,14 A. Beretvas,15
A. Bhatti,45 K.R. Bland,5 B. Blumenfeld,23 A. Bocci,14 A. Bodek,44 D. Bortoletto,43 J. Boudreau,42 A. Boveia,11
L. Brigliadoriii ,6 C. Bromberg,32 E. Brucken,21 J. Budagov,13 H.S. Budd,44 K. Burkett,15 G. Busettojj ,39
P. Bussey,19 P. Buttikk ,41 A. Buzatu,19 A. Calamba,10 S. Camarda,4 M. Campanelli,28 F. Canellicc ,11 B. Carls,22
D. Carlsmith,54 R. Carosi,41 S. Carrillol ,16 B. Casalj ,9 M. Casarsa,48 A. Castroii ,6 P. Catastini,20 D. Cauzqq rr ,48
V. Cavaliere,22 A. Cerrie ,26 L. Cerritoq ,28 Y.C. Chen,1 M. Chertok,7 G. Chiarelli,41 G. Chlachidze,15 K. Cho,25
D. Chokheli,13 A. Clark,18 C. Clarke,53 M.E. Convery,15 J. Conway,7 M. Corboy ,15 M. Cordelli,17 C.A. Cox,7
D.J. Cox,7 M. Cremonesi,41 D. Cruz,47 J. Cuevasx ,9 R. Culbertson,15 N. d’Ascenzou ,15 M. Dattaf f ,15
P. de Barbaro,44 L. Demortier,45 M. Deninno,6 M. D’Erricojj ,39 F. Devoto,21 A. Di Cantokk ,41 B. Di Ruzzap ,15
J.R. Dittmann,5 S. Donatikk ,41 M. D’Onofrio,27 M. Dorigoss ,48 A. Driuttiqq rr ,48 K. Ebina,52 R. Edgar,31
A. Elagin,47 R. Erbacher,7 S. Errede,22 B. Esham,22 S. Farrington,38 J.P. Fern´andez Ramos,29 R. Field,16
G. Flanagans ,15 R. Forrest,7 M. Franklin,20 J.C. Freeman,15 H. Frisch,11 Y. Funakoshi,52 C. Gallonikk ,41
A.F. Garfinkel,43 P. Garosill ,41 H. Gerberich,22 E. Gerchtein,15 S. Giagu,46 V. Giakoumopoulou,3 K. Gibson,42
C.M. Ginsburg,15 N. Giokaris,3 P. Giromini,17 V. Glagolev,13 D. Glenzinski,15 M. Gold,34 D. Goldin,47
A. Golossanov,15 G. Gomez,9 G. Gomez-Ceballos,30 M. Goncharov,30 O. Gonz´alez L´opez,29 I. Gorelov,34
A.T. Goshaw,14 K. Goulianos,45 E. Gramellini,6 C. Grosso-Pilcher,11 R.C. Group,51, 15 J. Guimaraes da Costa,20
S.R. Hahn,15 J.Y. Han,44 F. Happacher,17 K. Hara,49 M. Hare,50 R.F. Harr,53 T. Harrington-Taberm ,15
K. Hatakeyama,5 C. Hays,38 J. Heinrich,40 M. Herndon,54 A. Hocker,15 Z. Hong,47 W. Hopkinsf ,15 S. Hou,1
R.E. Hughes,35 U. Husemann,55 M. Husseinaa ,32 J. Huston,32 G. Introzzinnoo ,41 M. Ioripp ,46 A. Ivanovo ,7
E. James,15 D. Jang,10 B. Jayatilaka,15 E.J. Jeon,25 S. Jindariani,15 M. Jones,43 K.K. Joo,25 S.Y. Jun,10
T.R. Junk,15 M. Kambeitz,24 T. Kamon,25, 47 P.E. Karchin,53 A. Kasmi,5 Y. Katon ,37 W. Ketchumgg ,11 J. Keung,40
B. Kilminstercc ,15 D.H. Kim,25 H.S. Kim,25 J.E. Kim,25 M.J. Kim,17 S.H. Kim,49 S.B. Kim,25 Y.J. Kim,25
Y.K. Kim,11 N. Kimura,52 M. Kirby,15 K. Knoepfel,15 K. Kondo,52, ∗ D.J. Kong,25 J. Konigsberg,16 A.V. Kotwal,14
M. Kreps,24 J. Kroll,40 M. Kruse,14 T. Kuhr,24 M. Kurata,49 A.T. Laasanen,43 S. Lammel,15 M. Lancaster,28
K. Lannonw ,35 G. Latinoll ,41 H.S. Lee,25 J.S. Lee,25 S. Leo,41 S. Leone,41 J.D. Lewis,15 A. Limosanir ,14
E. Lipeles,40 A. Listera ,18 H. Liu,51 Q. Liu,43 T. Liu,15 S. Lockwitz,55 A. Loginov,55 D. Lucchesijj ,39 A. Luc`
a,17
J. Lueck,24 P. Lujan,26 P. Lukens,15 G. Lungu,45 J. Lys,26 R. Lysakd ,12 R. Madrak,15 P. Maestroll ,41 S. Malik,45
G. Mancab ,27 A. Manousakis-Katsikakis,3 L. Marchesehh ,6 F. Margaroli,46 P. Marinomm ,41 K. Matera,22
M.E. Mattson,53 A. Mazzacane,15 P. Mazzanti,6 R. McNultyi ,27 A. Mehta,27 P. Mehtala,21 C. Mesropian,45
T. Miao,15 D. Mietlicki,31 A. Mitra,1 H. Miyake,49 S. Moed,15 N. Moggi,6 C.S. Moony ,15 R. Mooreddee ,15
M.J. Morellomm ,41 A. Mukherjee,15 Th. Muller,24 P. Murat,15 M. Mussiniii ,6 J. Nachtmanm ,15 Y. Nagai,49
J. Naganoma,52 I. Nakano,36 A. Napier,50 J. Nett,47 C. Neu,51 T. Nigmanov,42 L. Nodulman,2 S.Y. Noh,25
O. Norniella,22 L. Oakes,38 S.H. Oh,14 Y.D. Oh,25 I. Oksuzian,51 T. Okusawa,37 R. Orava,21 L. Ortolan,4
C. Pagliarone,48 E. Palenciae ,9 P. Palni,34 V. Papadimitriou,15 W. Parker,54 G. Paulettaqq rr ,48 M. Paulini,10
C. Paus,30 T.J. Phillips,14 E. Pianori,40 J. Pilot,7 K. Pitts,22 C. Plager,8 L. Pondrom,54 S. Poprockif ,15
K. Potamianos,26 A. Pranko,26 F. Prokoshinz ,13 F. Ptohosg ,17 G. Punzikk ,41 I. Redondo Fern´andez,29 P. Renton,38
M. Rescigno,46 F. Rimondi,6, ∗ L. Ristori,41, 15 A. Robson,19 T. Rodriguez,40 S. Rollih ,50 M. Ronzanikk ,41
R. Roser,15 J.L. Rosner,11 F. Ruffinill ,41 A. Ruiz,9 J. Russ,10 V. Rusu,15 W.K. Sakumoto,44 Y. Sakurai,52
L. Santiqq rr ,48 K. Sato,49 V. Savelievu ,15 A. Savoy-Navarroy ,15 P. Schlabach,15 E.E. Schmidt,15 T. Schwarz,31
L. Scodellaro,9 F. Scuri,41 S. Seidel,34 Y. Seiya,37 A. Semenov,13 F. Sforzakk ,41 S.Z. Shalhout,7 T. Shears,27
P.F. Shepard,42 M. Shimojimat ,49 M. Shochet,11 I. Shreyber-Tecker,33 A. Simonenko,13 K. Sliwa,50 J.R. Smith,7
F.D. Snider,15 H. Song,42 V. Sorin,4 R. St. Denis,19, ∗ M. Stancari,15 D. Stentzv ,15 J. Strologas,34 Y. Sudo,49
A. Sukhanov,15 I. Suslov,13 K. Takemasa,49 Y. Takeuchi,49 J. Tang,11 M. Tecchio,31 P.K. Teng,1 J. Thomf ,15
E. Thomson,40 V. Thukral,47 D. Toback,47 S. Tokar,12 K. Tollefson,32 T. Tomura,49 D. Tonellie ,15 S. Torre,17
D. Torretta,15 P. Totaro,39 M. Trovatomm ,41 F. Ukegawa,49 S. Uozumi,25 F. V´azquezl ,16 G. Velev,15 C. Vellidis,15
3
46
Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,
pp
Sapienza Universit`
a di Roma, I-00185 Roma, Italy
Mitchell Institute for Fundamental Physics and Astronomy,
Texas A&M University, College Station, Texas 77843, USA
48
Istituto Nazionale di Fisica Nucleare Trieste, qq Gruppo Collegato di Udine,
rr
University of Udine, I-33100 Udine, Italy, ss University of Trieste, I-34127 Trieste, Italy
49
University of Tsukuba, Tsukuba, Ibaraki 305, Japan
50
Tufts University, Medford, Massachusetts 02155, USA
51
University of Virginia, Charlottesville, Virginia 22906, USA
52
Waseda University, Tokyo 169, Japan
53
Wayne State University, Detroit, Michigan 48201, USA
54
University of Wisconsin, Madison, Wisconsin 53706, USA
55
Yale University, New Haven, Connecticut 06520, USA
(Dated: October 21, 2014)
47
An updated measurement of the single top quark production cross section is presented using the
full data set collected by the Collider Detector at Fermilab (CDF) and corresponding to 9.5 fb−1
of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The
events selected contain an imbalance in the total transverse energy, jets identified as originating
from b quarks, and no identified leptons. The sum of the s- and t-channel single top quark cross
sections is measured to be 3.53+1.25
−1.16 pb and a lower limit on |Vtb | of 0.63 is obtained at the 95%
credibility level. These measurements are combined with previously reported CDF results obtained
from events with an imbalance in total transverse energy, jets identified as originating from b quarks,
and exactly one identified lepton. The combined cross section is measured to be 3.02+0.49
−0.48 pb and a
lower limit on |Vtb | of 0.84 is obtained at the 95% credibility level.
PACS numbers: 14.65.Ha, 13.85.Ni, 12.15.Hh
The observation of single top quark production at the
Tevatron was a significant achievement, allowing measurements of the cross section at a hadron collider [1] and
improved bounds on the Cabibbo-Kobayashi-Maskawa
(CKM) [2] matrix element magnitude |Vtb | due to the
direct coupling of the b quark with the singly produced
top quark.
For single top quark production, a t-¯b pair is produced
through a virtual W + boson [3] in either the s or t channel. The top quark subsequently decays to a W + boson
and a bottom quark, and the fragmentations of the b
and ¯b quarks result in two jets that can be reconstructed
in the detector. For the t-channel process, jets tend to
be more boosted along the proton-antiproton beam axis
than those originating from the s-channel process; some
of these jets are thus emitted in regions that are not instrumented and therefore escape the detector acceptance.
Excluding the contribution from the tW production
mode, which is expected to be negligible in the final state
considered in this Letter [4], the standard model (SM)
prediction for the combined s- and t-channel single top
s+t
quark production cross section σSM
is 3.15 ± 0.36 pb,
which has been calculated including next-to-next-toleading order corrections [5, 6]. The primary sensitivity to measuring this quantity is usually obtained from
events where the W boson from the t → W b process [7]
decays leptonically to a charged lepton ` (where ` represents either an electron e or muon µ) and an antineutrino,
with a pair of jets, one of which is “b-tagged” or identified as likely having originated from a bottom quark.
This sample of events (hereafter the “`νb¯b” sample) pro-
vides a distinctive signature against backgrounds produced by the strong interaction (QCD multijet or “MJ”
background), which contain no leptons and multiple jets.
A complementary approach consists in using final
states that contain two or three jets and significant imbalance in the total transverse energy 6ET [8], which results
from the leptonic decay of the W boson, where the lepton is not identified due to reconstruction or acceptance
effects and the neutrino carries significant unmeasured
momentum. Although MJ events comprise the dominant background in this final state (hereafter the “6ET b¯b”
analysis or sample), the requirement of significant 6ET
greatly suppresses such background. In addition, this
search has sensitivity to events where the W boson decays via W − → τ − ν¯τ , and the τ − decays hadronically,
resulting in a reconstructed jet signature.
The first CDF measurement of single top quark production in the 6ET b¯b final state was performed with a
data set corresponding to an integrated luminosity of
2.1 fb−1 [9]. This article presents a new measurement using the full CDF data set (9.5 fb−1 ). All the techniques
developed in the search for s-channel single top quark
production in the 6ET b¯b sample [10] are exploited in this
update. Important aspects of the analysis methodology
are restated here for completeness. The results of this
analysis and those of the most recent `νb¯b analysis [11]
are then combined to obtain a more precise measurement
of the single top quark cross section and to place a lower
limit on the CKM matrix element magnitude |Vtb |.
The CDF II detector is a multipurpose particle detector described in detail elsewhere [12]. It is comprised
arXiv:1410.5307v1 [hep-th] 20 Oct 2014
The scalar modes of the relic gravitons
Massimo Giovannini
1
Department of Physics, Theory Division, CERN, 1211 Geneva 23, Switzerland
INFN, Section of Milan-Bicocca, 20126 Milan, Italy
Abstract
In conformally flat background geometries the long wavelength gravitons can be described
in the fluid approximation and they induce scalar fluctuations both during inflation and in
the subsequent radiation-dominated epoch. While this effect is minute and suppressed for
a de Sitter stage of expansion, the fluctuations of the energy-momentum pseudo-tensor of
the graviton fluid lead to curvature perturbations that increase with time all along the postinflationary evolution. An explicit calculation of these effects is presented for a standard
thermal history and it is shown that the growth of the curvature perturbations caused by
the long wavelength modes is approximately compensated by the slope of the power spectra
of the energy density, pressure and anisotropic stress of the relic gravitons.
1
Electronic address: [email protected]
Cosmological evolution in a two-brane warped geometry model
Sumit Kumar, Anjan A Sen
arXiv:1410.5277v1 [astro-ph.CO] 20 Oct 2014
Center For Theoretical Physics
Jamia Millia Islamia, New Delhi 110025, India∗
Soumitra SenGupta
Department of Theoretical Physics
Indian Association for the Cultivation of Science
Kolkata 700032, India†
We study an effective 4-dimensional scalar-tensor field theory, originated from an underlying
brane-bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton
potential naturally emerges from the radion energy-momentum tensor which in turn results into an
inflationary model of the Universe on the visible brane that is consistent with the recent results from
the Planck’s experiment. The dynamics of modulus stabilization from the inflaton rolling condition
is demonstrated. The implications of our results in the context of recent BICEP2 results are also
discussed.
I.
INTRODUCTION
The standard cosmological paradigm, while successful in describing our observable Universe, is plagued with horizon
and flatness problems. Moreover, despite being able to explain the large scale structure formation due to some seed
fluctuations in our Universe, standard cosmology fails to provide a mechanism that can produce such seed fluctuations.
Inflationary models are at present the only way to provide solutions for these shortcomings in standard cosmology [1].
According to this paradigm , the Universe at an early epoch experienced an exponentially rapid expansion for a very
brief period due to some apparently repulsive gravity-like force. Such a scenario not only can successfully address the
horizon and flatness problems but at the same time, provides a theoretical set up to produce the primordial fluctuations
which later may act as a seed for large scale structure formation in the Universe. Amazingly the predicted primordial
fluctuations in any inflationary model [2] can be tested accurately through the measurement of temperature anisotropies
in the Cosmic Microwave Background Radiation as recently done by Planck experiment [3]. The construction of a
viable models for inflation, which are consistent with cosmological observations like Planck experiment, therefore is of
utmost importance and is a subject of study of the present work.
Among various models for inflation, the models with extra dimensions have been discussed by many authors [4].
Such models are independently considered in particle phenomenology due to their promise of resolving the wellknown naturalness/fine tuning problem in connection with stabilising the mass of Higgs boson against large radiative
corrections [5].
In this context, the 5-dimensional warped geometry model due to Randall and Sundrum ( RS ) [6] is very successfull
in offering a proper resolution to the naturalness problem without incorporating any intermediate scale other than
Plank/quantum gravity scale. The radius associated with the extra dimension in this model ( known as RS modulus )
acts as a parameter in the effective 4-dimensional theory and from a cosmological point of view, such a modulus can be
interpreted as a scalar field which, due to it’s time evolution, may drive the scale factor of our universe before getting
stabilized to a desired value. The well-known methodology to extract an effective or induce theory on a 3-brane from a
5-dimensional warped geometry model is demonstrated in [7] where using the Gauss-Codazzi equation with appropriate
junction condition in a two-brane warped geometry model and implementing a perturbative expansion in terms of the
∗ Electronic
† Electronic
address: [email protected], [email protected]
address: [email protected]
A Relativistic Many-Body Analysis of the Electric Dipole Moment of
1
1
223
Rn
B. K. Sahoo∗ , 1 Yashpal Singh and 2 B. P. Das
Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India and
Theoretical Physics and Astrophysics Group, Indian Institute of Astrophysics, Bangalore 560034, India∗
arXiv:1410.5270v1 [physics.atom-ph] 20 Oct 2014
2
We report the results of our ab initio relativistic many-body calculations of the electric dipole
moment (EDM) dA arising from the electron-nucleus tensor-pseudotensor (T-PT) interaction, the
interaction of the nuclear Schiff moment (NSM) with the atomic electrons and the electric dipole
polarizability αd for 223 Rn. Our relativistic random-phase approximation (RPA) results are substantially larger than those of lower-order relativistic many-body perturbation theory (MBPT) and
the results based on the relativistic coupled-cluster (RCC) method with single and double excitations (CCSD) are the most accurate to date for all the three properties that we have considered. We
obtain dA = 4.85(6) × 10−20 hσiCT |e| cm from T-PT interaction, dA = 2.89(4) × 10−17 S/(|e| f m3 )
from NSM interaction and αd = 35.27(9) ea30 . The former two results in combination with the
measured value of 223 Rn EDM, when it becomes available, could yield the best limits for the T-PT
coupling constant, EDMs and chromo-EDMs of quarks and θQCD parameter, and would thereby
shed light on leptoquark and supersymmetric models that predict CP violation.
PACS numbers: 32.10.Dk, 31.30.jp, 11.30.Er, 24.80.+y
The observation of an electric dipole moment (EDM)
of a non-degenerate system would be a signature of the
violations of parity (P) and time-reversal (T) symmetries
[1, 2]. T violation implies charge conjugation and parity
(CP) violation as a consequence of CPT invariance [3].
The standard model (SM) of elementary particle physics
is able to explain the observed CP violation in the decays of neutral K [4] and B [5] mesons, but the amount
of CP violation predicted by this model is not sufficient to
account for the matter-antimatter asymmetry in the Universe [6, 7]. The current limits for the electron EDM as
well as semi-leptonic and hadronic CP violating coupling
constants extracted by combining atomic EDM experiments and relativistic many-body calculations are several
orders of magnitude higher than the predictions of these
quantities by the SM [8–10]. This information cannot
be obtained from the ongoing experiments at the large
hadron collider (LHC) [11]. The study of atomic EDMs
could shed light on matter-antimatter asymmetry as the
origins of both these phenomena might lie beyond the
SM [12].
The EDM experiments on diamagnetic and paramagnetic atoms and molecules that are currently underway could improve the sensitivity of the current measurements by a few orders of magnitudes [13–19]. The
EDMs of diamagnetic atoms arise predominantly from
the electron-nucleus (e − N ) tensor-pseudotensor (T-PT)
interaction and interaction of electrons with the nuclear
Schiff moment (NSM) [20]. The e − N T-PT interaction
is due to the CP violating electron-nucleon (e − n) interactions which translates to CP violating electron-quark
(e − q) interactions at the level of elementary particles
that are predicted by leptoquark models [20]. The NSM,
on the other hand, could exist due to CP violating pionnucleon-nucleon (π − n − n) interactions and the EDM of
nucleons and both of them in turn could originate from
CP violating quark-quark (q − q) interactions or EDMs
and chromo-EDMs of quarks that are predicted by certain supersymmetric models [8–10]. In order to obtain
precise limits for the coupling constants of these interactions and EDMs of quarks, it is necessary to perform
both experiments and calculations as accurately as possible on suitable atoms.
According to the Schiff theorem [21], the EDM of a system vanishes if it is treated as point-like and in the nonrelativistic approximation even if its constituents have
nonzero EDMs. However, if relativistic and finite-size effects are taken into account, then they not only give rise
to a nonzero EDM of a composite system, but also play
an important role in enhancing it [22]. The EDM of a
composite system could be larger than those of its individual constituents due to their coherent contributions
and also the internal structure of these systems in some
cases can further enhance these effects overwhelmingly;
owing to which observations of EDMs in these systems
might be possible. In general, heavy atomic systems are
best suited for EDM measurements. A case in point is
the diamagnetic 223 Rn atom, which is sensitive to the
T-PT and NSM interactions.
The e − n T-PT interaction Hamiltonian is given by
[20, 23]
GF e−n ¯
ψe γ5 σµν ψe ψ¯n ιγ5 σµν ψn ,
HTe−n
−P T = √ CT
2
(1)
where CTe−n is the dimensionless e − n T-PT interaction
coupling coefficient, σµν = (γµ γν − γν γµ )/2 with γs are
the usual Dirac gamma-matrices and GF is the Fermi
constant. This corresponds to the e−N T-PT interaction
Hamiltonian (Hint ) in an atom as
X
√
T −P T
Hint ≡ HEDM
= i 2GF CT
σN · γe ρN (re ),
e
(2)
Nuclear Physics B
Proceedings
Supplement
Nuclear Physics B Proceedings Supplement 00 (2014) 1–7
HIP-2014-22/TH
Triplet Extended MSSM: Fine Tuning vs Perturbativity & Experiment
Priyotosh Bandyopadhyaya , Stefano Di Chiaraa,∗, Katri Huitua , Aslı Sabancı Kec¸elia
arXiv:1410.5397v1 [hep-ph] 20 Oct 2014
a Department
of Physics, University of Helsinki and Helsinki Institute of Physics, P.O.Box 64 (Gustaf H¨allstr¨omin katu 2), FIN-00014, Finland
Abstract
In this study we investigate the phenomenological viability of the Y = 0 Triplet Extended Supersymmetric Standard
Model (TESSM) by comparing its predictions with the current Higgs data from ATLAS, CMS, and Tevatron, as well
as the measured value of the Bs → X s γ branching ratio. We scan numerically the parameter space for data points
generating the measured particle mass spectrum and also satisfying current direct search constraints on new particles.
We require all the couplings to be perturbative up to the scale ΛUV = 104 TeV, by running them with newly calculated
two loop beta functions, and find that TESSM retains perturbativity as long as λ, the triplet coupling to the two Higgs
doublets, is smaller than 1.34 in absolute value. For |λ| > 0.8 we show that the fine-tuning associated to each viable
∼
data point can be greatly reduced as compared to values attainable in MSSM. Finally, we perform a fit by taking into
account 58 Higgs physics observables along with Br(Bs → X s γ), for which we calculate the NLO prediction within
TESSM. We find that, although naturality prefers a large |λ|, the experimental data disfavors it compared to the small
|λ| region, because of the low energy observable Br(Bs → X s γ).
Keywords: Higgs, Triplet Higgs, Supersymmetry
1. Introduction
Supersymmetric models remain among the best motivated extensions of the SM. In Minimal Supersymmetric Standard Model (MSSM) the desired Higgs mass can
be achieved with the help of radiative corrections for a
large mixing parameter, At , which in turn generates a
large splitting between the two physical stops [1], and/or
large stop soft squared masses. It was shown in [2] that
MSSM parameter regions allowed by the experimental
data require tuning smaller than 1%, depending on the
definition of fine-tuning. Such a serious fine-tuning can
be alleviated by having additional tree-level contributions to the Higgs mass, given that in MSSM the treelevel lightest Higgs is restricted to be lighter than mZ , so
∗ Corresponding
author
Email addresses: [email protected]
(Priyotosh Bandyopadhyay), [email protected]
(Stefano Di Chiara), [email protected] (Katri Huitu),
[email protected] (Aslı Sabancı Kec¸eli)
that sizable quantum corrections are no longer required.
In order to have additional contributions to the tree-level
lightest Higgs mass, one can extend the MSSM field
content by adding a triplet [3, 4, 5, 6, 7, 8, 9, 10] chiral superfield.
In light of fine-tuning considerations, here we consider the Triplet Extended Supersymmetric Standard
Model (TESSM)[3, 4]. The model we consider here
possesses a Y = 0 SU(2) triplet chiral superfield along
with the MSSM field content, where the extended Higgs
sector generates additional tree-level contributions to
the light Higgs mass and moreover may enhance the
light Higgs decay rate to diphoton [5, 7, 8, 9].
To assess the viability of TESSM for the current experimental data, we perform a goodness of fit analysis,
by using the results from ATLAS, CMS, and Tevatron
¯ as well as the
on Higgs decays to ZZ, WW, γγ, ττ, bb,
measured Bs → X s γ branching ratio, for a total of 59
observables.
Scattering Amplitudes in Gauge Theories
arXiv:1410.5256v1 [hep-ph] 20 Oct 2014
Diplomarbeit
of
Ulrich Schubert
June 6, 2013
Supervisor:
Prof. Dr. Wolfgang Hollik
Co-Supervisor:
Dr. Pierpaolo Mastrolia
Technische Universistät München
Physik-Department
Abstract
This thesis is focused on the development of new mathematical methods for computing multi-loop scattering amplitudes in gauge theories. In this work we combine, for
the first time, the unitarity-based construction for integrands, and the recently introduced integrand-reduction through multivariate polynomial division. After discussing
the generic features of this novel reduction algorithm, we will apply it to the one- and
two-loop five-point amplitudes in N = 4 sYM. The integrands of the multiple-cuts
are generated from products of tree-level amplitudes within the super-amplitudes formalism. The corresponding expressions will be used for the analytic reconstruction
of the polynomial residues. Their parametric form is known a priori, as derived by
means of successive polynomial divisions using the Gröbner basis associated to the
on-shell denominators. The integrand reduction method will be exploited to investigate the color-kinematic duality for multi-loop N = 4 sYM scattering amplitudes.
Our analysis yields a suggestive, systematic way to generate graphs which automatically satisfy the color-kinematic dualities. Finally, we will extract the leading
ultra-violet divergences of five-point one- and two-loop amplitudes in N = 4 sYM,
which represent a paradigmatic example for studying the UV behavior of supersymmetric amplitudes.
arXiv:1410.5247v1 [hep-ph] 20 Oct 2014
Prepared for submission to JHEP
Inverse magnetic catalysis and regularization in the
quark-meson model
Jens O. Andersena William R. Naylora Anders Tranbergb
a
Department of Physics, Norwegian University of Science and Technology, Høgskoleringen 5, N-7491 Trondheim, Norway
b
Faculty of Science and Technology, University of Stavanger, N-4036 Stavanger, Norway
E-mail: [email protected], [email protected],
[email protected]
Abstract: Motivated by recent work on inverse magnetic catalysis at finite temperature, we study
the quark-meson model using both dimensional regularization and a sharp cutoff. We calculate the
critical temperature for the chiral transition as a function of the Yukawa coupling in the mean-field
approximation varying the renormalization scale and the value of the ultraviolet cutoff. We show
that the results depend sensitively on how one treats the fermionic vacuum fluctuations in the model
and in particular on the regulator used. Finally, we explore a B-dependent transition temperature
for the Polyakov loop potential T0 (B) using the functional renormalization group. These results show
that even arbitrary freedom in the function T0 (B) does not allow for a decreasing chiral transition
temperature as a function of B. This is in agreement with previous mean-field calculations.
Keywords: Finite-temperature field theory, chiral transition, magnetic field
arXiv:1410.5241v1 [hep-ph] 20 Oct 2014
HEPHY-PUB 941/14
UWThPh-2014-23
October 2014
THE SPINLESS RELATIVISTIC YUKAWA
PROBLEM
Wolfgang LUCHA∗
Institute for High Energy Physics,
Austrian Academy of Sciences,
Nikolsdorfergasse 18, A-1050 Vienna, Austria
†
¨
Franz F. SCHOBERL
Faculty of Physics, University of Vienna,
Boltzmanngasse 5, A-1090 Vienna, Austria
Abstract
Noticing renewed or increasing interest in the possibility to describe semirelativistic bound
states (of either spin-zero constituents or, upon confining oneself to spin-averaged features,
constituents with nonzero spin) by means of the spinless Salpeter equation generalizing the
Schr¨odinger equation towards incorporation of effects caused by relativistic kinematics, we
revisit this problem for interactions between bound-state constituents of Yukawa shape, by
recalling and applying several well-known tools enabling to constrain the resulting spectra.
PACS numbers: 03.65.Pm, 03.65.Ge, 12.39.Pn, 11.10.St
Keywords: relativistic bound states, Bethe–Salpeter formalism, spinless Salpeter equation,
Rayleigh–Ritz variational technique, Yukawa potential
∗
†
E-mail address: [email protected]
E-mail address: [email protected]
arXiv:1410.5237v1 [hep-ph] 20 Oct 2014
Thermal properties of light tensor mesons via QCD
sum rules
K. Azizi†1, A. T¨
urkan∗2, E. Veli Veliev∗3, H. Sundu∗4
†
Department of Physics, Faculty of Arts and Sciences, Do˘gu¸s University
Acıbadem-Kadık¨oy, 34722 Istanbul, Turkey
∗
Department of Physics, Kocaeli University, 41380 Izmit, Turkey
1
e-mail:[email protected]
2
email:[email protected]
3
e-mail:[email protected]
4
email:[email protected]
Abstract
The thermal properties of light tensor mesons are investigated in the framework of
QCD sum rules at finite temperature. In particular, the masses and decay constants of
the light tensor mesons are calculated taking into account the new operators appearing
at finite temperature. The numerical results show that, near to the deconfinement
temperature, the decay constants decrease with amount of 6% compared to their
vacuum values. While, the masses diminish about 96%, 99% and 40% for f2 (1270),
a2 (1320) and K2∗ (1430) states, respectively. The results obtained at zero temperature
are in good consistency with the experimental data as well as existing theoretical
predictions.
PACS number(s): 11.10.Wx, 11.55.Hx, 14.40.Be, 14.40.Df
arXiv:1410.5234v1 [hep-ph] 20 Oct 2014
Semileptonic B → D transition in nuclear medium
K. Azizi1 ∗, N. Er2†, H. Sundu3‡
˙
Department of Physics, Do˘gu¸s University, Acıbadem-Kadık¨
oy, 34722 Istanbul,
Turkey
˙
Department of Physics, Abant Izzet
Baysal University, G¨
olk¨oy Kamp¨
us¨
u, 14980 Bolu, Turkey
1
2
3
˙
Department of Physics, Kocaeli University, 41380 Izmit,
Turkey
Abstract
We study the semileptonic tree-level B → D transition in the framework of QCD
sum rules in nuclear medium. In particular, we calculate the in-medium form factors
entering the transition matrix elements defining this decay channel. It is found that
the interactions of the participating particles with the medium lead to a considerable
suppression in the branching ratio compared to the vacuum.
PACS number(s):13.20.He, 21.65.Jk, 11.55.Hx
∗
e-mail: [email protected]
e-mail: [email protected]
‡
e-mail: [email protected]
†
Why mean pT is interesting
Michal Praszalowicz∗ and Larry McLerran†
arXiv:1410.5220v1 [hep-ph] 20 Oct 2014
∗
M. Smoluchowski Institute of Physics, Jagiellonian University,
S. Lojasiewicz str. 11, 30-348 Krakow, Poland.
†
Physics Dept, Bdg. 510A, Brookhaven National Laboratory, Upton, NY-11973, USA,
RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973, USA,
Physics Department, China Central Normal University, Wuhan, 430079, China.
Abstract. We discuss energy dependence of mean pT correlation with Nch basing on general features of high energy collisions
such as saturation and geometrical scaling. We use Color Glass Condensate calculation of an effective interaction radius that
scales as a third root of multiplicity, and then saturates. With this model input we construct scaling variable for hpT i(Nch ) at
different energies both for pp and pPb collisions, and show that recent ALICE data indeed does exhibit this scaling property.
We discuss energy dependence of the interaction radius and argue that since the radius cannot grow too large, a universal
behavior of hpT i for large multiplicities is expected.
Keywords: Saturation, geometrical scaling, interaction radius
PACS: 13.85.Hd, 12.38.Aw
Correlations are always interesting since they are sensitive to the fine details of interactions. For example standard
PYTHIA Monte Carlo fails in the case of hpT i correlation with Nch (see e.g. Refs. [1, 2]), while it does describe well
one particle spectra and total multiplicities. New effect called color recombination (see e.g. [3]) has to be added to
PYTHIA to take care of rather strong rise of hpT i with Nch . On the other hand newer MC generator EPOS [4] that has
saturation effects built in does not require special tuning to describe hpT i in function of Nch [1, 2]. In this talk that is
based on Refs. [5, 6] (and where an extensive list of references can be found) we shall study consequences of saturation
and geometrical scaling (GS) for mean transverse momenta at the LHC. Here the energy must be really large since
the character of hpT i dependence on Nch changes dramatically (see Fig. 1 in Ref. [7]) from the ISR energies (where
it decreases or stays constant) to the LHC energies (where it rises). Theoretical interest in hpT i correlation with Nch
goes back to the paper by L. van Hove [8] where he pointed out that qualitative change is expected in the presence
of the QCD phase transition. Today this motivation is perhaps less important since the QCD deconfining transition is
believed to be a soft crossover.
From the saturation point of view high energy central rapidity production of moderate pT particles can be viewed as
a result of a collision of two gluonic clouds characterized by one saturation scale that depends on gluon longitudinal
momenta x1 ∼ x2 denoted in the following as x:
x λ
0
Q2s (x) = Q20
(1)
x
where Q0 is an arbitrary scale parameter for which we take 1 GeV/c, and for x0 we take 10−3 .
An immediate consequence of (1) is GS of particle (or strictly speaking gluon) spectra [9]:
dNg
= S⊥ F (τ)
dyd 2 pT
where
τ=
p2T
Q2s (x)
(2)
(3)
is the scaling variable. Here S⊥ is a transverse area which will be specified later. Logarithmic corrections due the
running of the strong coupling constant are neglected in Eq. (2).
In order to integrate (2) over d 2 pT we have to change variables to dτ which gives
dNg
= A S⊥ Q¯ 2s (W )
dy
(4)
arXiv:1410.5175v1 [hep-ph] 20 Oct 2014
EPJ Web of Conferences will be set by the publisher
DOI: will be set by the publisher
c Owned by the authors, published by EDP Sciences, 2014
Single and double charmed meson production at the LHC
Rafal Maciula1 , a and Antoni Szczurek1,2
1
2
Institute of Nuclear Physics PAN, PL-31-342 Cracow, Poland
University of Rzeszów, PL-35-959 Rzeszów, Poland
Abstract. We discuss production of charmed mesons in proton-proton collisions at the
LHC. The cross section for inclusive production of c¯c pairs is calculated in the framework
of the k⊥ -factorization approach which effectively includes next-to-leading order corrections. Theoretical uncertainties of the model related to the choice of renormalization and
factorization scales as well as due to the quark mass are discussed. Results of the k⊥ factorization approach are compared to NLO parton model predictions. The hadronization of charm quarks is included with the help of the Peterson fragmentation functions.
Inclusive differential distributions in transverse momentum for several charmed mesons
(D0 , D± , D±S ) are calculated and compared to recent results of the ALICE, ATLAS and
LHCb collaborations. Furthermore, we also discuss production of two pairs of c¯c within
a simple formalism of double-parton scattering (DPS). Surprisingly large cross sections,
comparable to single-parton scattering (SPS) contribution, are predicted for LHC energies. We compare our predictions for double charm production (DD meson-meson pairs)
with recent results of the LHCb collaboration for azimuthal angle ϕDD and rapidity distance between mesons YDD . Meson-meson kinematical correlations are also confronted
with those related to the standard meson-antimeson measurements. Our calculations
clearly confirm the dominance of DPS in the production of events with double charm,
however some strength seems to be still lacking. Possible missing contribution within the
framework of single-ladder-splitting DPS mechanism is also discussed.
1 Introduction
Recently, ATLAS [1], ALICE [2, 3] and LHCb [4] collaborations have measured inclusive distributions for different charmed mesons. The LHCb collaboration has measured in addition a few correlation observables for charmed meson-antimeson pairs in the forward region 2 < y < 4 [5].
Commonly in the exploration of heavy quark production the main efforts concentrate on inclusive
distributions. Improved schemes of standrad pQCD NLO collinear approach are state of art in this
respect. On the other hand, the kt -factorization approach is commonly used as a very efficient tool
for more exclusive studies of kinematical correlations (see e.g. [6] and references therein). In this
approach the transverse momenta of incident partons are explicitly taken into account and their emission is encoded in the unintegrated gluon distributions (UGDFs). This allows to construct different
correlation distributions which are strictly related to the transverse momenta of initial particles.
a e-mail: [email protected]
EPHOU-14-018
Unification of SUSY breaking and GUT breaking
Tatsuo Kobayashi1 and Yuji Omura2
arXiv:1410.5173v1 [hep-ph] 20 Oct 2014
1
Department of Physics, Hokkaido University, Sapporo 060-0810, Japan
2
Department of Physics, Nagoya University, Nagoya 464-8602, Japan
(Dated: October 21, 2014)
Abstract
We build explicit supersymmetric unification models where grand unified gauge symmetry breaking and supersymmetry (SUSY) breaking are caused by the same sector. Besides, the SM-charged
particles are also predicted by the symmetry breaking sector, and they give the soft SUSY breaking
terms through the so-called gauge mediation. We investigate the mass spectrums in an explicit
model with SU (5) and additional gauge groups, and discuss its phenomenological aspects. Especially, nonzero A-term and B-term are generated at one-loop level according to the mediation via
the vector superfields, so that the electro-weak symmetry breaking and 125 GeV Higgs mass may
be achieved by the large B-term and A-term even if the stop mass is around 1 TeV.
1
Nuclear Physics B
Proceedings
Supplement
Nuclear Physics B Proceedings Supplement 00 (2014) 1–7
Bounds on neutral and charged Higgs from the LHC
Victor Ilisie
arXiv:1410.5164v1 [hep-ph] 20 Oct 2014
Departament de F´ısica Te`orica, IFIC, Universitat de Val`encia – CSIC, Apt. Correus 22085, E-46071 Val`encia, Spain
Abstract
After the discovery of a Standard Model-like boson with mass of about 125 GeV the possibility of an enlarged
scalar sector arises naturally. Here we present the current status of the phenomenology of the two-Higgs-doublet
models with a special focus on the charged Higgs sector. If one considers a fermiophobic charged Higgs (it does not
couple to fermions at tree level), all present experimental bounds are evaded trivially, therefore one needs to consider
other decay and production channels. In this work we also present some of the interesting features of this specific
scenario.
Keywords: charged Higgs, beyond Standard Model
2. The Two-Higgs-Doublet Model
adopt the conventions Mh ≤ MH and 0 ≤ α˜ ≤ π therefore, sin α˜ is positive.
The most generic Yukawa Lagrangian with the SM
fermionic content gives rise to dangerous tree level
flavour changing neutral currents (FCNCs) which are
phenomenologically suppressed. In order to get rid
of them one usually imposes a discrete Z2 symmetry.
Here we consider the more generic approach given by
the aligned two-Higgs-doublet model (A2HDM) [2]. In
terms of the the mass-eigenstate fields the Yukawa Lagrangian reads
√
i
2 +n h
LY = −
H u¯ ςd V Md PR − ςu Mu† VPL d
v
o
+ ςl ν¯ Ml PR l
i
1 X ϕ0i 0 h ¯
−
y f ϕi f M f PR f + h.c.
v 0
The 2HDM extends the SM with a second scalar
doublet of hypercharge Y = 21 . The physical scalar
spectrum contains five degrees of freedom: the two
charged fields H ± (x) and three neutral scalars ϕ0i (x) =
{h(x), H(x), A(x)}, which are related with the S i fields
through an orthogonal transformation ϕ0i (x) = Ri j S j (x).
A detailed discussion is given in [1]. In this work we
5
where PR,L ≡ 1±γ
2 and where ς f ( f = u, d, l) are called
the alignment parameters. These three parameters are
independent, flavour universal, scalar basis independent
and in general complex. Their phases introduce new
sources of CP-violation and the usual models based
on Z2 symmetries are recovered taking the appropriate
limits [2]. The couplings of the neutral scalar fields are
1. Introduction
The discovery of a Higgs-like boson constitutes a
great motivation in our quest for a deeper understanding
of the scalar sector. Now that we have proven experimentally that this sector exists, one question that arises
naturally is, are there more scalars? The simplest extension of the SM, which has a richer scalar sector and that
could give rise to new interesting phenomenology also
in the flavour physics sector is the Two-Higgs-Doublet
Model (2HDM) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
14, 15, 16]. Next we shall present the phenomenology
of the scalar sector of this model and see how the new
LHC data together with the flavour constraints affects
its parameter space.
ϕi , f
Universality of Hard-Loop Action
Alina Czajka
Institute of Physics, Jan Kochanowski University, Kielce, Poland
Stanislaw Mr´owczy´
nski
arXiv:1410.5117v1 [hep-ph] 19 Oct 2014
Institute of Physics, Jan Kochanowski University, Kielce, Poland and
National Centre for Nuclear Research, Warsaw, Poland
(Dated: October 19, 2014)
The effective actions of gauge bosons, fermions and scalars, which are obtained within the hardloop approximation, are shown to have unique forms for a whole class of gauge theories including
QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs
irrespective of a field content of each theory and of variety of specific interactions. Consequently,
the long-wavelength or semiclassical features of plasma systems governed by these theories such as
collective excitations are almost identical. An origin of the universality is discussed.
I.
INTRODUCTION
The hard-loop approach is a practical tool to describe plasma systems governed by QED or QCD in a gauge
invariant way which is free of infrared divergences, see the reviews [1–4]. Initially the approach was developed within
the thermal field theory [5, 6] but it was soon realized that it can be formulated in terms of quasiclassical kinetic
theory [7, 8]. The plasma systems under consideration were assumed to be in thermodynamical equilibrium but the
methods can be naturally generalized to plasmas out of equilibrium [9, 10].
An elegant and concise formulation of the hard-loop approach is achieved by introducing an effective action derived
for equilibrium and non-equilibrium systems in [11–13] and [9, 14], respectively. The action is a key quantity that
encodes an infinite set of hard-loop n-point functions. A whole gamut of long-wavelength characteristics of a plasma
system is carried by the functions. In particular, the two-point functions or self-energies provide response functions like
permeabilities or susceptibilities which control various screening lengths. The self-energies also determine a spectrum
of collective excitations (quasiparticles) that is a fundamental characteristics of any many-body system.
One wonders how much a given plasma characteristics is different for different plasma systems. It has been known
for a long time that the self-energies of gauge bosons in the long-wavelength limit are of the same structure for QED
and QCD plasmas [15]. Consequently, the collective excitations and many other characteristics are the same in the two
plasma systems [16]. Comparing systematically supersymmetric plasmas to their non-supersymmetric counterparts,
we have considered [17–19] a whole class of gauge theories including Abelian cases: QED, scalar QED, and N = 1
super QED and nonAbelian ones: pure Yang-Mills, QCD, and N = 4 super Yang-Mills. We have observed that the
self-energies of gauge bosons, fermions and scalars, which are computed in the hard-loop approximation, have unique
structures for all considered theories irrespective of a field content and of variety of specific interactions. Consequently,
the hard-loop effective actions are essentially the same and so are long-wavelength characteristics of plasma systems
governed by the gauge theories of interest. Although our findings are partially presented in [17–19], we have decided
to collect all our results in this paper and to systematically elaborate on the problem. We explain an origin of the
universality, that is, how it happens that the microscopically different systems are very similar to each other in the
long-wavelength limit. Physical consequences of the universality are also discussed.
Our paper is organized as follows. In the next section, we briefly present the gauge theories taken into consideration.
The differences and similarities of the theories are underlined. Sec. III is devoted to the self-energies of gauge bosons,
fermions and scalars which are computed in the hard-loop approximation. Knowing the self-energies, the effective
action of the hard-loop approach is derived in Sec. IV. An origin of the universality of the hard-loop action and its
physical consequences are discussed in Sec. V which concludes our study.
Throughout the paper we use the natural system of units with c = ~ = kB = 1; our choice of the signature of the
metric tensor is (+ − −−).
II.
GAUGE THEORIES UNDER CONSIDERATION
We briefly present here the gauge theories under consideration stressing differences and similarities among them.
We start with QED of the commonly known Lagrangian density that is
1
¯ / Ψ,
LQED = − F µν Fµν + iΨD
4
(1)
Z → b¯b in non-minimal Universal Extra Dimensional Model
Tapoja Jha1 , Anindya Datta2
Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road,
Kolkata 700009, India
arXiv:1410.5098v1 [hep-ph] 19 Oct 2014
Abstract
We calculate the effective Zb¯b coupling at one loop level, in the framework of non-minimal
Universal Extra Dimensional (nmUED) model. Non-minimality in the Universal Extra Dimensional (UED) framework is realized by adding kinetic terms with arbitrary coefficients to the
action at the boundary points of the extra space like dimension. A recent estimation of the
Standard Model (SM) contribution to Zb¯b coupling at two loop level, points to a 1.2σ discrepancy between the experimental data and SM estimate. We compare our calculation with the
difference between the SM prediction and experimental estimation of the above coupling and
constrain the parameter space of nmUED. We also review the limit on compactification radius of
UED in view of the new theoretical estimation of SM contribution to Zb¯b coupling. For suitable
choice of BLKT parameters, 95% C.L. lower limit on R−1 comes out to be in the ballpark of a
TeV in the framework of nmUED; while in UED, the lower limit on R−1 is 505 GeV which is a
significant improvement over an earlier estimate.
PACS No: 11.10 Kk, 12.60.-i, 14.70.Hp, 14.80.Rt
1
Introduction
Extra Dimensional theories can offer unique solutions to many long standing puzzles of Standard
Model (SM) such as gauge coupling unifications [1] and fermion mass hierarchy [2]. Most importantly
they can provide a Dark Matter candidate of the universe [3]. In this article, we are interested in
a particular incarnation of extra dimensional theory referred as Universal Extra Dimensional Model
(UED) where all the SM fields can propagate in 4 + 1 dimensional space-time, the extra dimension
(say, y) being compactified on a circle (S 1 ) of radius R [4]. The five dimensional action consists
of the same fields of SM and would respect the same SU(3)c × SU(2)L × U(1)Y gauge symmetry
also. R−1 is the typical energy scale at which the four dimensional effective theory would start to
show up the dynamics of Kaluza-Klein (KK) excitations of SM fields. The masses of KK- modes
2
are m2n = m2 + Rn 2 ; where n is an integer, called KK-number which corresponds to the discretized
momentum in the compactified dimension, y. m is any mass parameter that has been attributed to
the respective five dimensional field. The n = 0 mode fields in the effective theory could be identified
with the SM particles.
To generate the correct structure of chiral fermions in SM, one needs to impose some extra
symmetry on the action called orbifolding which is nothing but a discrete Z2 symmetry : y → −y.
The fields which have zero mode are chosen to be even under this Z2 symmetry. There are KKexcitations of other fields which are odd under this transformation. Consequently they cannot have
1
2
[email protected]
[email protected]
1
Proceedings of the Second Annual LHCP
arXiv:1410.5093v1 [hep-ph] 19 Oct 2014
Higgs Physics Beyond the Standard Model
Margarete Muhlleitner
Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe,
Germany
ABSTRACT
Higgs physics beyond the Standard Model (SM) is presented in the context of an
underlying strong dynamics of electroweak symmetry breaking (EWSB) as given
by composite Higgs models. Subsequently, the study of New Physics (NP) effects
in a more model-independent way through the effective Lagrangian approach is
briefly sketched before moving on to the investigation of NP through Higgs
coupling measurements. Depending on the precision on the extracted couplings,
NP scales up to the TeV range can be probed at the high-luminosity option of
the LHC, if the coupling deviations arise from mixing effects or from some
underlying strong dynamics.
PRESENTED AT
The Second Annual Conference
on Large Hadron Collider Physics
Columbia University, New York, U.S.A
June 2-7, 2014
Jet-dilepton conversion in spherical expanding quark-gluon plasma
Yong-Ping Fu and Qin Xi
Department of Physics, Lincang Teachers College, Lincang 677000, China
arXiv:1410.5044v1 [hep-ph] 19 Oct 2014
(Dated: October 21, 2014)
We calculate the production of large mass dileptons from the jet-dilepton conversion in spherical
expanding quark-gluon plasma at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider
(LHC) energies. The jet-dilepton conversion exceeds the thermal dilepton production and Drell-Yan
process in the
√large mass region of 4.5 GeV< M <5.5 GeV and 7 GeV< M <9 GeV in central Pb+Pb
collisions at sNN =2.76 TeV and 5.5 TeV, respectively. We present the solution of 1+3 dimensional
fluid hydrodynamics with spherical symmetry. We find that the transverse flow leads to a rapid
cooling of the fire ball. The suppression due to transverse flow is also important at intermediate and
large mass at LHC energies. The energy loss of jets in the hot and dense medium is also included.
PACS numbers: 25.75.-q, 12.38.Mh
I.
INTRODUCTION
One of the most important aim in the experiments of
relativistic heavy-ion collisions is that of the study of a
quark-gluon plasma (QGP). The electromagnetic radiation is considered to be a useful probe for the investigation of the evolution of the QGP due to their very long
mean free path in the medium [1].
In relativistic heavy-ion collisions dileptons are produced from several sources. These include the dileptons
from the Drell-Yan process of primary partons [2], thermal dileptons from the interactions of thermal partons in
the QGP [3] and the hadron interactions in the hadronic
phase [4, 5], and dileptons from the hadronic decays occurring after the freeze-out [6]. Energetic jets produced
via the parton scattering in relativistic heavy-ion collisions also provide an excellent tool that enables tomographic study of the dense medium [7, 8]. In Refs. [9, 10]
the authors indicated that the electromagnetic radiation
from jets interacting with the QGP is a further source.
The jet-dilepton conversion in the 1+1 dimensional (1+1
D) evolution of the plasma has been investigated [11–13].
The exact solutions of the relativistic hydrodynamical equations can describe the collective properties of the
strongly interacting matter. The Bjorken solution provides an estimate of the 1+1 D cylindrical expansion of
the plasma [14]. The 1+3 dimensional (1+3 D) hydrodynamics have been calculated numerically which assumes
cylindrical symmetry along the transverse direction and
boost invariant along the longitudinal direction [15–18].
After the initial proper time τi and initial temperature
Ti the system is regarded as thermalized. The system
temperature T are given as a function of proper time τ
by the numerical calculation of the flow. The transverse
flow effect of the dilepton production from the QGP, with
cylindrical symmetry, are shown to be important in the
region of low invariant mass [17]. In the present work,
we derive the hubble-like solutions (τ T = τi Ti ) of 1+3 D
relativistic hydrodynamics which favors spherical symmetry, and investigate the initial condition of the temperature T and proper time τ in the spherical evolution.
We find the transverse flow effect is also apparent at in-
termediate and high invariant mass at LHC energies.
Jets crossing the hot and dense plasma will lose
their energies. For high energy partons, the radiative energy loss is dominant over the elastic energy loss
[19]. The jet energy loss through gluon bremsstrahlung
in the medium has been elaborated by several models: Gyulassy-Wang (GW) [19, 20], Gyulassy-Levai-Vitev
(GLV) [21, 22], Baier-Dokshitzer-Mueller-Peigne-Schiff
(BDMPS) [23, 24], Guo-Wang (HT) [25, 26], WangHuang-Sarcevic (WHS) [27, 28], and Arnold-Moore-Yaffe
(AMY) [29–31]. In Ref. [9–12] the authors use the AMY
formalism to investigate the electromagnetic signature of
jet-plasma interactions. The AMY formalism assumes
that hard jets evolve in the 1+1 D medium according
to the Fokker-Planck rate equations for their momentum
distributions dN jet /dE. Energy loss is described as a dependence of the parton momentum distribution on time.
In this paper we use the WHS and BDMPS frameworks
to calculate the energy loss of the momentum distribution
of jets passing through the QGP in the 1+3 D spherical
symmetry.
This paper is organized as follows. In Sec. II we discuss
the 1+3 D spherical evolution of the plasma. In Sec. III
we calculate the jet production and jet energy loss. In
Sec. IV we rigorously derive the production rate for the
jet-dilepton conversion by using the relativistic kinetic
theory. The Drell-Yan process is also presented in Sec.
V. Finally, the summary and numerical discussion are
presented in Sec. VI.
II.
1+3 DIMENSION HYDRODYNAMICS
In this section we begin with the equation for conservation of energy-momentum
∂µ T µν = 0,
(1)
the energy-momentum tensor of an ideal fluid produced
in relativistic heavy-ion collisions is given by
T µν = (ε + P )uµ uν − P g µν ,
(2)
THEORETICAL CALCULATIONS FOR PREDICTED STATES OF HEAVY
QUARKONIUM VIA NON-RELATIVISTIC FRAME WORK
A. M. Yasser1,*, G. S. Hassan2 and T. A. Nahool1 +
1
Physics Department, Faculty of Science at Qena, South Valley University, Egypt
2
Physics Department, Faculty of Science, Assuit University, Egypt
*
+
[email protected]
[email protected]
Abstract
In this paper, we calculate the mass spectra of heavy quarkonium by using matrix Numerov's method to make
the predictions of F and G states for further experiments. The method gives a very reasonable result which is in a
good agreement with other methods and with recently published theoretical data. From the yielded wave functions we calculate the root mean square radius 𝑟𝑚𝑠 and β coefficients of heavy quarkonium.
Keywords
Matrix Numerov's method; wave functions; β coefficient; root mean square radius; heavy quarkonium.
1. Introduction
The theoretical studies of the heavy quarkonium system [1] and its applications to bottomonium [2] and charmonium [3] is one of the special interest because of its relies entirely on the first principles of quantum chromo
dynamics( QCD). From the viewpoint of the "heavy quarkonium" spectra, we calculate the theoretical mass
spectra via non-relativistic frame work [4], [5], [6] by using matrix Numerov's method [7], [8] in two levels F
and G. Many studies investigate "heavy quarkonium" properties within the quark model [9-15]. An essential
progress has been made in the theoretical investigation of the non-relativistic heavy quark dynamics. Our point
of departure is to calculate the spectra of heavy quarkonium and the corresponding wave functions of nn states
(n = c, b) for the predicted F and G states. Actually, we don’t have any experimental data of F and G states.
Therefore, we compare the present theoretical predictions with published theoretical data from [16], [17] and
[18]. Moreover, the heavy-meson wave functions determined in this work can be employed to make predictions
of other properties. Besides, the main motivation is to calculate the root mean square radius rms of different
states for bottomonium and the numerical values of β coefficient [19], which can be used to calculate the decay
widths [20], and differential cross sections [21] for quarkonium states. In this work, we consider the mass spectra and some properties of heavy quarkonium systems in the non-relativistic quark model using matrix Numerov's method. In section 2, we review the main formalism of the matrix Numerov's method used in our analysis
and the used model. Besides, the analytical formula of the wave functions. Some characteristics properties of
bottomonium mesons are introduced in section 3. After that, numerical results and discussion are given. Finally
in the last section, we summarize our main results and conclusions.
2. Theoretical Basis
2.1. Matrix Numerov’s Method
The Matrix Numerov’s method is a method that provides us an approximate solution of non-relativistic
Schrödinger equation of the form:
arXiv:1410.4942v1 [hep-ph] 18 Oct 2014
The Higgs-like boson spin from the center-edge
asymmetry in the diphoton channel
P. Osland,a,1 A. A. Pankov,b,2 and A. V. Tsytrinovb,3
a
Department of Physics and Technology, University of Bergen, Postboks 7803,
N-5020 Bergen, Norway
b
The Abdus Salam ICTP Affiliated Centre, Technical University of Gomel,
246746 Gomel, Belarus
Abstract
We discuss the discrimination of the 125 GeV spin-parity 0+ Higgs-like boson observed
at the LHC, decaying into two photons, H → γγ, against the hypothesis of a minimally
coupled J P = 2+ narrow diphoton resonance with the same mass and giving the same
total number of signal events under the peak. We apply, as the basic observable of the
analysis, the center-edge asymmetry ACE of the cosine of the polar angle of the produced
photons in the diphoton rest frame to distinguish between the tested spin hypotheses. We
show that the center-edge asymmetry ACE should provide strong discrimination between
the possibilities of spin-0 and spin-2 with graviton-like couplings, with a confidence level
up to 8σ depending on the fraction of q q¯ production of the spin-2 signal.
1
[email protected]
E-mail: [email protected]
3
E-mail: [email protected]
2
arXiv:1410.4940v1 [hep-ph] 18 Oct 2014
The Pressure of Misalignment Axions: a Difference from WIMPs in Galaxy Formation?
Sacha Davidson1
1
IPN de Lyon/CNRS, Universit´e Lyon 1, Villeurbanne, France
DOI: will be assigned
Two populations of axions can contribute to cold dark matter: the classical field produced
via the misalignment mechanism, and the modes produced in the decay of strings. The
classical field has extra pressure, as compared to WIMPs, which could have observable
consequences in non-linear galaxy formation.
1
Introduction
It is interesting to study whether axion dark matter could be distinguished from WIMP dark
matter, using Large Scale Structure (LSS) data. It is well known that axion dark matter can
be composed of two components[1]: the misalignment axions and the non-relativistic modes
radiated by strings (here taken to be cold particles). Both redshift like CDM, and grow linear
density inhomogeneities like WIMPs. However, as pointed out by Sikivie [2], the misalignment
axions have a different pressure from WIMPs, which could be relevant during non-linear stucture
formation. The consequences of this additional pressure could be reliably addressed by the
numerical galaxy formation community. The aim of this proceedings, which is based on [3], is
to clarify the relevant variables and equations for studying non-linear stucture formation with
axions.
There has been considerable confusion in the literature about whether axion dark matter is
a Bose Einstein condensate. In a scenario proposed by Sikivie, the dark matter axions “thermalise” via their gravitational interactions, and therefore form a Bose Einstein condensate due
to the high occupation number of the low momentum modes. Then, Sikivie and collaborators
hypothesize that a galactic halo made of condensate could form vortices, which could be observed as caustics in the dark matter distribution. This interesting scenario, which proposes
an observable signature for axion dark matter in LSS data, has been studied by many people:
Saikawa and collaborators[4] confirmed in Quantum Field Theory and General Relativity, the
gravitational interaction rate estimated by Sikivie and collaborators. However, with Martin
Elmer[5], we could not confirm that the interaction rate was a thermalisation rate (= generated
entropy). Rindler-Daller and Shapiro[6] studied rotating halos of non-relativistic scalar field,
and found that vortices were energetically favoured for much lighter bosons than the QCD
axion, or for scalars with repulsive self-interactions (opposite to axions, whose self-interactions
are attractive). This proceedings will argue that the notion of Bose Einstein condensation is an
unneccessary confusion, somewhat akin to trying to describe a classical electromagnetic field
in terms of photons. The misalignment axions are a classical scalar field, as such they have a
Patras 2014
1
JLAB-THY-14-1965
LA-UR-14-28032
Nucleon Tensor Charge from Collins Azimuthal Asymmetry Measurements
Zhong-Bo Kang,1, ∗ Alexei Prokudin,2, † Peng Sun,3, ‡ and Feng Yuan3, §
1
arXiv:1410.4877v1 [hep-ph] 17 Oct 2014
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
2
Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606, USA
3
Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
(Dated: October 21, 2014)
We investigate the nucleon tensor charge from current experiments by a combined analysis of the
Collins asymmetries in two hadron production in e+ e− annihilations and single inclusive hadron
production in deep inelastic scattering processes. The transverse momentum dependent evolution
is taken into account, for the first time, in the global fit of the Collins fragmentation functions
and the quark transversity distributions at the approximate next-to-leading logarithmic order. We
obtain the nucleon tensor charge contribution from up and down quarks as: δu = +0.30+0.12
−0.11 and
2
δd = −0.20+0.35
−0.13 at 90% of confidence level for momentum fraction 0.0065 ≤ xB ≤ 0.35 and Q =
2
10 GeV .
PACS numbers: 12.38.Bx, 12.39.St, 13.85.Hd, 13.88.+e
Introduction. — Nucleon tensor charge is one of the
fundamental properties of the proton and its determination is among the main goals of existing and future experimental facilities [1–6]. It also plays an important role
in constraining the nuclear physics aspects for probing
new physics beyond the standard model, and has been
an active subject from lattice QCD calculations [7, 8].
In terms of the partonic structure of the nucleon, the
tensor charge is constructed from the quark transversity
distribution, one of the three leading-twist quark distributions. However, the experimental exploration of the
quark transversity distribution in high energy scattering
is difficult, because it is a chiral-odd distribution and has
to be coupled with another chiral-odd function in a physical process [2].
An important channel to investigate the quark
transversity distribution is to measure the Collins azimuthal asymmetries in semi-inclusive hadron production in deep inelastic scattering (SIDIS), where the
transversity distribution is coupled to the chiral-odd
Collins fragmentation function (FF) [9], as well as backto-back two hadron production in e+ e− annihilations
where two Collins FFs are coupled to each other [10].
There have been great experimental efforts from both
DIS and e+ e− facilities to explore the Collins asymmetries, including HERMES [11, 12], COMPASS [13] and
JLab [14] in DIS experiments, and BELLE [15, 16] and
BABAR [17] at e+ e− colliders of B-factories. Due to the
universality of the Collins fragmentation functions [18],
we will be able to combine the analysis of these two
processes to constrain the quark transversity distributions. Earlier results of the phenomenological studies in
Refs. [19–21] have demonstrated the powerful reach of the
Collins asymmetry measurements in accessing the quark
transversity distributions and eventually the nucleon tensor charge. In this paper, we go beyond the leading order
(LO) framework of Refs. [19–21], and take into account
the important higher order corrections, including, in par-
ticular, the large logarithms [22, 23].
Theoretically, the large logarithms in the above hard
processes are controlled by the relevant QCD evolution,
i.e., the transverse momentum dependent (TMD) evolution [22, 23]. It has been pointed out in Ref. [24] that
the TMD evolution plays an important role in evaluating the Collins asymmetries. Because of the large energy difference between the existing DIS and e+ e− experiments [11–17], the QCD evolution effects have to be
carefully examined when one extracts the quark transversity distributions. In this paper, for the first time, we
demonstrate that the TMD evolution can describe the experimental data and constrain the nucleon tensor charge
with improved theoretical accuracy. To achieve that, we
include the most recent developments from both theory
and phenomenology sides [25–34] and apply the TMD
evolution at the next-to-leading-logarithmic (NLL) order
within the Collins-Soper-Sterman (CSS) [22, 23] formalism. We show that our results improve the theoretical
description of the experimental data in various aspects,
especially, in formulating the transverse momentum dependence of the asymmetries in e+ e− annihilations [17].
The quark transversity distribution has also been an
important subject to explore other transverse spin related phenomena, such as the di-hadron fragmentation
processes [35, 36], and inclusive hadron production at
large transverse momentum in single transversely polarized pp collisions [37–39]. Our results will provide an
important cross check and a step further toward a global
analysis of all these spin asymmetries associated with the
quark transversity distributions.
Collins Asymmetries in SIDIS and e+ e− annihilation.
— In SIDIS, a lepton scatters off the nucleon target N ,
and produces an identified hadron h in the final state,
lN → lhX. The Collins effect leads to a transverse spin
sin(φ +φ )
asymmetry: σ(S⊥ ) ∼ FUU (1 + AUT h s sin(φh + φs )),
where φs and φh are the azimuthal angles of the nu~⊥ and the transcleon’s transverse polarization vector S
Azimuthal asymmetries and the emergence of “collectivity” from multi-particle
correlations in high-energy pA collisions
Adrian Dumitru∗
Department of Natural Sciences, Baruch College, CUNY,
17 Lexington Avenue, New York, NY 10010, USA and
The Graduate School and University Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
Larry McLerran†
RIKEN BNL, Brookhaven National Laboratory, Upton, NY 11973
Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA and
Physics Department, China Central Normal University, Wuhan, China
arXiv:1410.4844v1 [hep-ph] 17 Oct 2014
Vladimir Skokov‡
Department of Physics, Western Michigan University, Kalamazoo, MI 49008, USA
We show how angular asymmetries ∼ cos 2φ can arise in dipole scattering at high energies. We
illustrate the effects due to anisotropic fluctuations of the saturation momentum of the target with
a finite correlation length in the transverse impact parameter plane, i.e. from a domain-like structure. We compute the two-particle azimuthal cumulant in this model including both one-particle
factorizable as well as genuine two-particle non-factorizable contributions to the two-particle cross
section. We also compute the full BBGKY hierarchy for the four-particle azimuthal cumulant and
find that only the fully factorizable contribution to c2 {4} is negative while all contributions from
genuine two, three and four-particle correlations are positive. Our results provide some insight into
the origin of azimuthal asymmetries in p+Pb collisions at the LHC which reveal a change of sign of
c2 {4} in high-multiplicity events.
I.
INTRODUCTION
Large azimuthal asymmetries have been observed in p+Pb collisions at the LHC [1–3] and in d+Au collisions at
RHIC [4]. These asymmetries are usually measured via multi-particle angular correlations (see below) and were found
to extend over a long range in rapidity. Causality then requires that the correlations originate from the earliest times
of the collision [5]. Furthermore, the data shows that the asymmetries persist up to rather high transverse momenta,
well beyond p⊥ ∼ 1 GeV. Therefore, it is important to develop an understanding of their origin in terms of semi-hard
(short distance) QCD dynamics [6–13].
∗ Electronic
address: [email protected]
address: [email protected]
‡ Electronic address: [email protected]
† Electronic
Galactic Centre GeV Photons from Dark Technicolor
Matti Heikinheimo1 and Christian Spethmann1
1
National Institute of Chemical Physics and Biophysics, R¨
avala 10, 10143 Tallinn, Estonia
(Dated: October 21, 2014)
arXiv:1410.4842v1 [hep-ph] 17 Oct 2014
We present a classically scale-invariant model with a confining dark sector, which is coupled to the
Standard Model through the Higgs portal. The galactic centre gamma ray excess can be explained
in this model by collision-induced dark matter decays to b-quarks. We discuss the possibility to
obtain the dark matter relic density through thermal freeze-out, which however requires excessive
fine-tuning. We then instead focus on a freeze-in scenario and perform detailed calculations and a
parameter scan. We find that the observed relic density and the gamma ray excess can be explained
by a wide range of parameters in this model.
I.
INTRODUCTION
During the last decades, much effort has been spent
to search for evidence of dark matter annihilation in the
Milky Way. Gamma rays offer the most intriguing possible signal, because they travel unperturbed through the
interstellar medium from the source to the detectors, and
can be unambiguously observed. For some year now it
has been know that there is an apparent excess of 1-3
GeV gamma rays in Fermi-LAT data from the galactic
centre [1–7] and the inner regions of the galaxy [8, 9].
In addition, it has been noted that data from the
PAMELA experiment [10–12] also exhibit a 40% excess of
antiprotons in the 1-3 GeV energy range over expetations
from cosmic ray propagation models [13–15]. Miraculously, both excesses can be generated by the same 30-40
GeV dark matter annihilating into b¯b with a thermally
averaged cross section of hσvi ≈ (1.4 − 2) 10−26 cm3 /s
[16, 17]. As noted in [18], this setup naturally occurs
in Higgs-portal dark matter models in the presence of a
scalar resonance.
In this paper we show how the observed photon and
antiproton excesses can be explained by the collisioninduced decays of composite dark matter in a classically
scale-invariant model. In this setup [19–22], here referred
to as Dark Technicolor, the electroweak scale is generated
dynamically in a strongly interacting hidden sector and
mediated to the SM via a Higgs portal interaction with
a messenger singlet. The stable dark matter candidate is
a composite state, i.e. a dark technipion or dark technibaryon.
The coupling between the visible sector and the dark
sector through the Higgs portal is necessarily weak to
avoid LHC and direct detection constraints. This means
that thermal freeze-out is not a viable way to generate a
sufficiently small relic density unless the dark matter annihilation process is enhanced by an s-channel resonance,
which requires a fine-tuned mass spectrum. Instead, we
propose that the observed dark matter can be generated
via freeze-in if the couplings of the messenger scalar are
sufficiently small.
We will present our setup in section II. In section III
we discuss in detail the origin of the gamma-ray signal.
In section IV we discuss dark matter generation through
the freeze-in mechanism in the early universe. In section
VI we conclude and discuss further implications of the
model.
II.
THE DARK TECHNICOLOR MODEL
The dark technicolor model consists of a confining dark
sector, i.e., dark techniquarks Q charged under a nonAbelian gauge group SU (N )TC , and a scalar messenger
S that is a singlet under all gauge groups. The model,
including the SM, is taken to be classically scale invariant, so that any explicit mass terms are absent at tree
level. As the dark technicolor sector becomes confining
at a scale ΛTC , the messenger field obtains a vacuum
expectation value, which in turn generates an effective
negative mass squared term for the Higgs via a Higgs
portal coupling. Electroweak symmetry breaking then
proceeds as in the SM.
The Lagrangian of the model is given by
Nf
X
1
a
/ i
L = |Dµ H|2 + |∂µ S|2 − F aµν Fµν
Q¯i iDQ
+
4
i=1
1
−λh |H|4 − λS |S|4 + λSh |S|2 |H|2
4
Nf
X
−(
yQi S Q¯i Qi + h.c.) + LSM,mH =0 ,
(1)
i=1
where LSM,mH =0 contains the SM gauge and fermion
sectors, including the usual Yukawa couplings with the
Higgs, but no explicit Higgs mass term. H is the Higgs
a
doublet, H = √12 (0, h + v) in the unitary gauge. Fµν
is the field strength of the dark technicolor gauge group,
and Nf is the number of flavors in the hidden sector. The
singlet messenger scalar S has Yukawa couplings with the
hidden sector quarks, parametrized by yQi , which are assumed to be flavour diagonal.
The confinement and chiral symmetry breaking results
in Pseudo-Nambu-Goldstone bosons—massive dark technipions, which are our dark matter candidate. In the
absence of explicit chiral symmetry breaking terms these
particles would be massless, but here the chiral symmetry of the dark technicolor sector is explicitly broken by
Effects of pion potential and nuclear symmetry energy on the
π − /π + ratio in heavy-ion collisions at beam energies around the
pion production threshold
Wen-Mei Guo1,2,3 , Gao-Chan Yong1,4,5 ,∗ Hang Liu6 , and Wei Zuo1,4,5
arXiv:1410.4926v1 [nucl-th] 18 Oct 2014
1
Institute of Modern Physics,
Chinese Academy of Sciences,
Lanzhou 730000, China
2
School of Physical Science and Technology,
Lanzhou University,
Lanzhou 730000, China
3
University of Chinese Academy of Sciences,
Beijing 100049, China
4
State Key Laboratory of Theoretical Physics,
Institute of Theoretical Physics,
Chinese Academy of Sciences,
Beijing, 100190
5
Kavli Institute for Theoretical Physics,
Chinese Academy of Sciences,
Beijing 100190, China
6
Texas Advanced Computing Center
(TACC) University of Texas at Austin,
Austin, Texas 78758, USA
(Dated: October 21, 2014)
1
arXiv:1410.5375v1 [nucl-ex] 20 Oct 2014
Energy Dependence of K/π, p/π, and K/p Fluctuations in Au+Au Collisions from
√
sNN = 7.7 to 200 GeV
N. M. Abdelwahab57 , L. Adamczyk1 , J. K. Adkins23 , G. Agakishiev21 , M. M. Aggarwal35, Z. Ahammed53 ,
I. Alekseev19 , J. Alford22 , C. D. Anson32 , A. Aparin21 , D. Arkhipkin4 , E. C. Aschenauer4 , G. S. Averichev21 ,
A. Banerjee53 , D. R. Beavis4 , R. Bellwied49 , A. Bhasin20 , A. K. Bhati35 , P. Bhattarai48 , J. Bielcik13 , J. Bielcikova14 ,
L. C. Bland4 , I. G. Bordyuzhin19 , W. Borowski45, J. Bouchet22 , A. V. Brandin30 , S. G. Brovko6, S. B¨
ultmann33 ,
I. Bunzarov21, T. P. Burton4 , J. Butterworth41 , H. Caines58 , M. Calder´
on de la Barca S´
anchez6 , J. M. Campbell32 ,
D. Cebra6 , R. Cendejas36 , M. C. Cervantes47 , P. Chaloupka13 , Z. Chang47 , S. Chattopadhyay53, H. F. Chen42 ,
J. H. Chen44 , L. Chen9 , J. Cheng50 , M. Cherney12 , A. Chikanian58 , W. Christie4 , J. Chwastowski11,
M. J. M. Codrington48 , G. Contin26 , J. G. Cramer55 , H. J. Crawford5, X. Cui42 , S. Das16 , A. Davila Leyva48 ,
L. C. De Silva12 , R. R. Debbe4 , T. G. Dedovich21 , J. Deng43 , A. A. Derevschikov37, R. Derradi de Souza8 ,
B. di Ruzza4 , L. Didenko4 , C. Dilks36 , F. Ding6 , P. Djawotho47 , X. Dong26 , J. L. Drachenberg52 , J. E. Draper6 ,
C. M. Du25 , L. E. Dunkelberger7 , J. C. Dunlop4 , L. G. Efimov21 , J. Engelage5 , K. S. Engle51 , G. Eppley41 ,
L. Eun26 , O. Evdokimov10 , O. Eyser4, R. Fatemi23 , S. Fazio4 , J. Fedorisin21 , P. Filip21 , Y. Fisyak4 , C. E. Flores6 ,
C. A. Gagliardi47 , D. R. Gangadharan26, D. Garand38 , F. Geurts41 , A. Gibson52 , M. Girard54 , S. Gliske2 ,
L. Greiner26 , D. Grosnick52 , D. S. Gunarathne46 , Y. Guo42 , A. Gupta20 , S. Gupta20 , W. Guryn4 , B. Haag6 ,
A. Hamed47 , L-X. Han44 , R. Haque31 , J. W. Harris58 , S. Heppelmann36 , A. Hirsch38 , G. W. Hoffmann48 ,
D. J. Hofman10 , S. Horvat58 , B. Huang4 , H. Z. Huang7 , X. Huang50 , P. Huck9 , T. J. Humanic32 , G. Igo7 ,
W. W. Jacobs18 , H. Jang24 , E. G. Judd5 , S. Kabana45, D. Kalinkin19 , K. Kang50 , K. Kauder10 , H. W. Ke4 ,
D. Keane22 , A. Kechechyan21, A. Kesich6 , Z. H. Khan10 , D. P. Kikola54, I. Kisel15 , A. Kisiel54 , D. D. Koetke52 ,
T. Kollegger15, J. Konzer38 , I. Koralt33 , L. K. Kosarzewski54, L. Kotchenda30 , A. F. Kraishan46 , P. Kravtsov30,
K. Krueger2, I. Kulakov15, L. Kumar35 , R. A. Kycia11 , M. A. C. Lamont4 , J. M. Landgraf4 , K. D. Landry7 ,
J. Lauret4 , A. Lebedev4 , R. Lednicky21 , J. H. Lee4 , C. Li42 , W. Li44 , X. Li38 , X. Li46 , Y. Li50 , Z. M. Li9 ,
M. A. Lisa32 , F. Liu9 , T. Ljubicic4 , W. J. Llope56 , M. Lomnitz22 , R. S. Longacre4, X. Luo9 , G. L. Ma44 ,
Y. G. Ma44 , D. P. Mahapatra16, R. Majka58 , S. Margetis22 , C. Markert48 , H. Masui26 , H. S. Matis26 ,
D. McDonald49 , T. S. McShane12 , N. G. Minaev37 , S. Mioduszewski47 , B. Mohanty31 , M. M. Mondal47 ,
D. A. Morozov37, M. K. Mustafa26 , B. K. Nandi17 , Md. Nasim7 , T. K. Nayak53 , J. M. Nelson3 , G. Nigmatkulov30 ,
L. V. Nogach37, S. Y. Noh24 , J. Novak29 , S. B. Nurushev37 , G. Odyniec26 , A. Ogawa4, K. Oh39 , A. Ohlson58 ,
V. Okorokov30, E. W. Oldag48 , D. L. Olvitt Jr.46 , B. S. Page18, Y. X. Pan7 , Y. Pandit10 , Y. Panebratsev21,
T. Pawlak54, B. Pawlik34, H. Pei9 , C. Perkins5, P. Pile4 , M. Planinic59 , J. Pluta54 , N. Poljak59 , K. Poniatowska54,
J. Porter26, A. M. Poskanzer26, N. K. Pruthi35 , M. Przybycien1, J. Putschke56 , H. Qiu26 , A. Quintero22 ,
S. Ramachandran23 , R. Raniwala40 , S. Raniwala40 , R. L. Ray48 , C. K. Riley58 , H. G. Ritter26 , J. B. Roberts41 ,
O. V. Rogachevskiy21, J. L. Romero6 , J. F. Ross12 , A. Roy53 , L. Ruan4 , J. Rusnak14 , O. Rusnakova13,
N. R. Sahoo47 , P. K. Sahu16 , I. Sakrejda26 , S. Salur26 , A. Sandacz54 , J. Sandweiss58 , E. Sangaline6 , A. Sarkar17,
J. Schambach48 , R. P. Scharenberg38 , A. M. Schmah26 , W. B. Schmidke4 , N. Schmitz28 , J. Seger12 ,
P. Seyboth28 , N. Shah7 , E. Shahaliev21 , P. V. Shanmuganathan22 , M. Shao42 , B. Sharma35 , W. Q. Shen44 ,
S. S. Shi26 , Q. Y. Shou44 , E. P. Sichtermann26 , M. Simko13 , M. J. Skoby18 , D. Smirnov4 , N. Smirnov58 ,
D. Solanki40 , P. Sorensen4 , H. M. Spinka2 , B. Srivastava38 , T. D. S. Stanislaus52 , J. R. Stevens27 ,
R. Stock15 , M. Strikhanov30 , B. Stringfellow38 , M. Sumbera14 , X. Sun26 , X. M. Sun26 , Y. Sun42 , Z. Sun25 ,
B. Surrow46 , D. N. Svirida19 , T. J. M. Symons26 , M. A. Szelezniak26 , J. Takahashi8 , A. H. Tang4 , Z. Tang42 ,
T. Tarnowsky29, J. H. Thomas26 , A. R. Timmins49 , D. Tlusty14 , M. Tokarev21 , S. Trentalange7, R. E. Tribble47 ,
P. Tribedy53 , B. A. Trzeciak13 , O. D. Tsai7 , J. Turnau34 , T. Ullrich4 , D. G. Underwood2 , G. Van Buren4 ,
G. van Nieuwenhuizen27 , M. Vandenbroucke46 , J. A. Vanfossen, Jr.22 , R. Varma17 , G. M. S. Vasconcelos8 ,
A. N. Vasiliev37 , R. Vertesi14 , F. Videbæk4 , Y. P. Viyogi53 , S. Vokal21 , A. Vossen18 , M. Wada48 , F. Wang38 ,
G. Wang7 , H. Wang4 , J. S. Wang25 , X. L. Wang42 , Y. Wang50 , Y. Wang10 , G. Webb4 , J. C. Webb4 ,
G. D. Westfall29 , H. Wieman26 , S. W. Wissink18 , Y. F. Wu9 , Z. Xiao50 , W. Xie38 , K. Xin41 , H. Xu25 , J. Xu9 ,
N. Xu26 , Q. H. Xu43 , Y. Xu42 , Z. Xu4 , W. Yan50 , C. Yang42 , Y. Yang25 , Y. Yang9 , Z. Ye10 , P. Yepes41 , L. Yi38 ,
K. Yip4 , I-K. Yoo39 , N. Yu9 , H. Zbroszczyk54 , W. Zha42 , J. B. Zhang9 , J. L. Zhang43 , S. Zhang44 , X. P. Zhang50 ,
Y. Zhang42 , Z. P. Zhang42 , F. Zhao7 , J. Zhao9 , C. Zhong44 , X. Zhu50 , Y. H. Zhu44 , Y. Zoulkarneeva21 , M. Zyzak15
1
AGH University of Science and Technology, Cracow 30-059, Poland
2
Argonne National Laboratory, Argonne, Illinois 60439, USA
2
3
University of Birmingham, Birmingham B15 2TT, United Kingdom
4
Brookhaven National Laboratory, Upton, New York 11973, USA
5
University of California, Berkeley, California 94720, USA
6
University of California, Davis, California 95616, USA
7
University of California, Los Angeles, California 90095, USA
8
Universidade Estadual de Campinas, Sao Paulo 13131, Brazil
9
Central China Normal University (HZNU), Wuhan 430079, China
10
University of Illinois at Chicago, Chicago, Illinois 60607, USA
11
Cracow University of Technology, Cracow 31-155, Poland
12
Creighton University, Omaha, Nebraska 68178, USA
13
Czech Technical University in Prague, FNSPE, Prague, 115 19, Czech Republic
14
ˇ z/Prague, Czech Republic
Nuclear Physics Institute AS CR, 250 68 Reˇ
15
Frankfurt Institute for Advanced Studies FIAS, Frankfurt 60438, Germany
16
Institute of Physics, Bhubaneswar 751005, India
17
Indian Institute of Technology, Mumbai 400076, India
18
Indiana University, Bloomington, Indiana 47408, USA
19
Alikhanov Institute for Theoretical and Experimental Physics, Moscow 117218, Russia
20
University of Jammu, Jammu 180001, India
21
Joint Institute for Nuclear Research, Dubna, 141 980, Russia
22
Kent State University, Kent, Ohio 44242, USA
23
University of Kentucky, Lexington, Kentucky, 40506-0055, USA
24
Korea Institute of Science and Technology Information, Daejeon 305-701, Korea
25
Institute of Modern Physics, Lanzhou 730000, China
26
Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
27
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA
28
Max-Planck-Institut fur Physik, Munich 80805, Germany
29
Michigan State University, East Lansing, Michigan 48824, USA
30
Moscow Engineering Physics Institute, Moscow 115409, Russia
31
National Institute of Science Education and Research, Bhubaneswar 751005, India
32
Ohio State University, Columbus, Ohio 43210, USA
33
Old Dominion University, Norfolk, Virginia 23529, USA
34
Institute of Nuclear Physics PAN, Cracow 31-342, Poland
35
Panjab University, Chandigarh 160014, India
36
Pennsylvania State University, University Park, Pennsylvania 16802, USA
37
Institute of High Energy Physics, Protvino 142281, Russia
38
Purdue University, West Lafayette, Indiana 47907, USA
39
Pusan National University, Pusan 609735, Republic of Korea
40
University of Rajasthan, Jaipur 302004, India
41
Rice University, Houston, Texas 77251, USA
42
University of Science and Technology of China, Hefei 230026, China
43
Shandong University, Jinan, Shandong 250100, China
44
Shanghai Institute of Applied Physics, Shanghai 201800, China
45
SUBATECH, Nantes 44307, France
46
Temple University, Philadelphia, Pennsylvania 19122, USA
47
Texas A&M University, College Station, Texas 77843, USA
48
University of Texas, Austin, Texas 78712, USA
49
University of Houston, Houston, Texas 77204, USA
50
Tsinghua University, Beijing 100084, China
51
United States Naval Academy, Annapolis, Maryland, 21402, USA
52
Valparaiso University, Valparaiso, Indiana 46383, USA
53
Variable Energy Cyclotron Centre, Kolkata 700064, India
54
Warsaw University of Technology, Warsaw 00-661, Poland
55
University of Washington, Seattle, Washington 98195, USA
56
Wayne State University, Detroit, Michigan 48201, USA
57
World Laboratory for Cosmology and Particle Physics (WLCAPP), Cairo 11571, Egypt
58
Yale University, New Haven, Connecticut 06520, USA and
59
University of Zagreb, Zagreb, HR-10002, Croatia
(Dated: October 21, 2014)
A search for the quantum chromodynamics (QCD) critical point was performed by the STAR
experiment at the Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle
pairs. Heavy-ion collisions were studied over a large range of collision energies with homogeneous
acceptance and excellent particle identification, covering a significant range in the QCD phase
diagram where a critical point may be located. Dynamical K/π, p/π, and K/p fluctuations as
8
He nuclei stopped in nuclear track emulsion
D. A. Artemenkov, A. A. Bezbakh, V. Bradnova, M. S. Golovkov, A. V. Gorshkov,
S. A. Krupko, N. K. Kornegrutsa, V. V. Rusakova, R. S. Slepnev,
S. V. Stepantsov, A. S. Fomichev, P. I. Zarubin,∗ and I. G. Zarubina
arXiv:1410.5188v1 [nucl-ex] 20 Oct 2014
Joint Insitute for Nuclear Research, Dubna, Russia
G. Kaminsky
Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
R. R. Kattabekov
Institute for Physics and Technology,
Uzbek Academy of Sciences, Tashkent, Republic of Uzbekistan
K. Z. Mamatkulov
Djizak State Pedagogical Institute, Djizak, Republic of Uzbekistan
R. Stanoeva
SouthWest University, Blagoevgrad, Bulgaria
V. Chudoba
Institute of Physics, Silesian University in Opava, Czech Republic
(Dated: October 21, 2014)
1
Clustering features of the 7 Be nucleus in relativistic fragmentation
N. K. Kornegrutsa, D. A. Artemenkov, P. I. Zarubin,∗ and I. G. Zarubina
Joint Insitute for Nuclear Research, Dubna, Russia
R. R. Kattabekov
arXiv:1410.5162v1 [nucl-ex] 20 Oct 2014
Institute for Physics and Technology,
Uzbek Academy of Sciences, Tashkent, Republic of Uzbekistan
K. Z. Mamatkulov
Djizak State Pedagogical Institute, Djizak, Republic of Uzbekistan
(Dated: October 21, 2014)
Abstract
Charge topology of fragmentation of 1.2 A GeV 7 Be nuclei in nuclear track emulsion is presented.
The dissociation channels 4 He + 3 He, 23 He+ n, 4 He + 21 H are considered in detail. It is established
that the events 6 Be + n amount about to 27 % in the channel 4 He + 21 H.
PACS numbers: 21.45.+v, 23.60+e, 25.10.+s
∗
Electronic address: [email protected]; URL: http://becquerel.jinr.ru
1