1. No category

TMDs and PVDIS: JLab 6 GeV results and 12 GeV Plan
J. P. Chen , Jefferson Lab
APFB2014, Hahndorf, Australia, April 7-11, 2014
 TMDs with 6 GeV JLab: Exploration
Recent and new results with a transversely Polarized 3He (n)
Collins/Sivers/Worm-gear asymmetries on pions and Kaons
Inclusive hadron and electron SSA
 JLab 12 GeV Plan for TMD study: Precision Multi-d Mapping
SoLID Program on TMDs
 PVDIS with 6 GeV JLab: New Results
 12 GeV plan for PVDIS: SoLID Program
JLab 12 GeV Upgrade
The completion of the 12 GeV
Upgrade of CEBAF was
ranked the highest priority in
the 2007 NSAC Long Range
Plan.
New Hall
Add 5
cryomodules
20 cryomodules
CHL-2
Add arc
20 cryomodules
Add 5
cryomodules
Enhanced capabilities in
existing Halls
Increase of Luminosity
1035 - ~1039 cm-2s-1
Maintain capability to deliver
lower pass beam energies :
2.2, 4.4, 6.6,….
5D Dist.
Wpu(x,kT,r ) Wigner distributions
d2k T
d 2 rT
GPDs/IPDs
TMD PDFs
f1u(x,kT), ..
h1u(x,kT) 3D
d2k
T
PDFs
f1u(x), .. h1u(x)
imaging
dx &
Fourier Transformation
d 2 rT
1D
Form
Factors
GE(Q2),
GM(Q2)
Leading-Twist TMD PDFs
Quark polarization
Unpolarized
(U)
Nucleon Polarization
U
f1 =
Boer-Mulders
g1 =
f 1T =
Transversely Polarized
(T)
h1 =
L
T
Longitudinally
Polarized (L)
h1L =
Helicity
Worm Gear
h1 =Transversity
Sivers
g1T =
Worm Gear
h1T =
Pretzelosity
Nucleon Spin
Quark Spin
: Probed with transversely pol target
HERMES, COMPASS, JLab E06-010



Gold mine for TMDs
Access all eight leading-twist TMDs
through spin-comb. & azimuthalmodulations
Tagging quark flavor/kinematics
Status of Transverse Spin/TMD Study
•
Large single spin asymmetry in pp->pX (Fermi, RHIC-spin)
•
Collins Asymmetries
- sizable for the proton (HERMES and COMPASS)
large at high x, p- and p+ has opposite sign
unfavored Collins fragmentation as large as favored (opposite sign)?
- consistent with 0 for the deuteron (COMPASS)
• Sivers Asymmetries
- non-zero for p+ from proton (HERMES), new COMPASS data
- large for K+ ?
•
•
•
•
•
Collins Fragmentation from Belle
Global Fits/models: Anselmino et al., Yuan et al., Pasquini et al., Ma et al., …
Very active theoretical and experimental efforts
JLab (6 GeV and 12 GeV), RHIC-spin, Belle, FAIR, J-PARC, EIC, …
First neutron measurement from Hall A 6 GeV (E06-010)
SoLID with polarized p and n(3He) at JLab 12 GeV
Unprecedented precision with high luminosity and large acceptance
Single Spin Asymmetries with
A Transversely Polarized 3He (n)
JLab Hall A E06-010
Published and Preliminary Results
From SIDIS and Inclusive Reactions
SIDIS: Separation of Collins, Sivers and pretzelocity
effects through angular dependence


1
N

N
AUT ( hl ,  Sl ) 
P N + N
Collins
Sivers
 AUT
sin(h + S ) + AUT
sin(h  S )
ty
+ AUPretzelosi
sin(3h  S )
T
Collins
UT
A
 sin(h + S )
Sivers
AUT
 sin(h  S )
UT
UT
 h1  H

1
 f1T  D1
AUPretzelosity
 sin(3h  S )
T
UT
 h1T  H1
E06-010 Experiment
Spokespersons: J. P. Chen, E. Cisbani, H. Gao, X. Jiang and J. C. Peng
3

He (e , eK  ) X

7 PhD Thesis Students (graduated) + 2 new students
• First measurement on n (3He)
• Transversely Polarized 3He Target
• Polarized Electron Beam, 5.9 GeV
Luminosity
Monitor
• BigBite at 30º as Electron Arm
– Pe = 0.7 ~ 2.2 GeV/c
• HRSL at 16º as Hadron Arm
– Ph = 2.35 GeV/c
– Excellent PID for p/K/p
Beam Polarimetry
(Møller + Compton)
9
3He
(n) Target Single-Spin Asymmetry in SIDIS
E06-010 collaboration, X. Qian at al., PRL 107:072003(2011)
n  (e,e' h),h  p + , p 
neutron Collins SSA small
Non-zero at highest x for p+
neutron Sivers SSA:
negative for π+,
Agree with Torino Fit
Blue band: model (fitting) uncertainties
Red band: other systematic uncertainties
Asymmetry ALT Result
J. Huang et al., PRL. 108, 052001 (2012).
To leading twist:
cos(h s )
LT
A
cos(h s )
LT
F
 g D
q
1T
h
1q
Dominated by L=0 (S) and L=1 (P) interference
• neutron ALT : Positive for p• Consist w/ model in signs, suggest larger asymmetry
Worm-Gear
Trans helicity
Pretzelosity Results on Neutron
Analysis by Y. Zhang (Lanzhou) and X. Qian (Caltech)
Extracted Pretzelosity Asymmetries, 𝑨𝑼𝑻𝐬𝐢𝐧(𝝋𝒉
− 𝝋𝒔), 𝐨𝐧 𝐭𝐡𝐞 𝐧𝐞𝐮𝐭𝐫𝐨𝐧
New Results
In models,
directly related
to OAM,
L=0 and L=2
interference
submitted to PRC, arXiv:1312.3047
E06-010: Inclusive Hadron SSA (AN)
Analysis by K, Allada (JLab), Y. Zhao (USTC),
σUT
 
  
 S N  l xPh ∼sin  S 


 

S N  l xPh  0
 
 S = 900 
sin  S
UT
A
• Clear
non-zero vertical target SSA
• Opposite sign for p+ and p
• Large for
K+
PRC 89, 042201 (2014)
vertical target
E06-010: Inclusive Hadron SSA (AN)


 

S N  l xPh  0
 
 S = 90 0 
sin  S
AUT
• Clear non-zero target SSA
• Opposite sign for p+ and p
• AN at low pT not very well
understood
• Results consistent with
predictions based on Sivers
mechanism (valid at high pT )
vertical target
Inclusive Target Single Spin Asymmetry: DIS





Ay (Q 2 )  
 + 
θ
3He
e-

• Unpolarized e- beam incident on 3He target polarized normal to the
electron scattering plane.
• However, Ay=0 at Born level,
 sensitive to physics at order α2; two-photon exchange.
• In DIS case: related to integral of Sivers
• Physics Importance discussed in A. Metz’s paper
Inclusive Target Single-Spin Asymmetry
Analysis by J. Katech(W&M), X. Qian (Caltech),
submitted to PRL, arXiv:1311.0197
Extracted neutron SSA from 3He(e,e’)
• Results show 2-photon
effects
• Consistent with A. Metz’s
prediction: 2-photon
interact with 2 quarks and
q-g-q correlator from
Torino fit for Sivers (solid
black)
• Disagree with predictions
based on KQW q-g-q
correlator (red-dashed)
• Disagree with predictions
based on 2-photon interact
with 1 quark (blue dashed)
Future: TMD study 12 GeV JLab
Precision Study of TMDs
In the Valence Quark Region
JLab 12 GeV Era: Precision Study of TMDs
•
•
•
•
•
From exploration to precision study with 12 GeV JLab
Transversity: fundamental PDFs, tensor charge
TMDs: 3-d momentum structure of the nucleon
 Quark orbital angular momentum
Multi-dimensional mapping of TMDs
• 4-d (x,z,P┴,Q2)
• Multi-facilities, global effort
• Precision  high statistics
• high luminosity and large acceptance
SoLID for SIDIS/PVDIS with 12 GeV JLab
• Exciting physics program:
Five approved experiments:
three SIDIS “A rated”, one PVDIS “A rated”, one J/Psi “A- rated”
• International collaboration: nine countries and 50+ institutions
• GEMs for tracking
• Cherenkov and EM
Calorimeter for electron PID
• Heavy Gas Cherenkov and
MRPC (TOF) for pion PID
• CLEOII Magnet (official)
• pCDR just completed
Mapping of Collins(Sivers) Asymmetries with SoLID
E12-10-006 (n) Spokespersons: J. P. Chen, H. Gao, X. Jiang, J. C. Peng and X. Qian
E12-11-108(p): K. Allada, J. P. Chen, H. Gao, X. Li and Z. E. Meziani
Both Approved with “A” Rating
• Both p+ and p• Precision Map in
region
x(0.05-0.65)
z(0.3-0.7)
Q2(1-8)
PT(0-1.6)
• <10% d quark
tensor charge
Collins (Sivers) Asymmetries
Expected Improvement: Sivers Function
f 1T =
• Significant Improvement in the valence quark (high-x) region
• Illustrated in a model fit (from A. Prokudin)
E12-11-107:
Worm-gear functions (A
rating )
Spokespersons: J. P. Chen, J. Huang, Y. Qiang and W. Yan
g1T =
Longi-transversity
Trans-helicity
Center of points:
• Dominated by real part of interference
between L=0 (S) and L=1 (P) states
• No GPD correspondence
• Lattice QCD -> Dipole Shift in mom. space.
• Model Calculations -> h1L =? -g1T .
h1L =
ALT ~ g1T ( x) D1 ( z )
AUL ~ h 1L ( x) H 1 ( z )

Access transversity in
transversely polarized
neutron target through π+
π- di-hadron production
Asymmetry projection for one M-z bin


Run simultaneously with
SIDIS 3He (e,e’π±)X
Systematical check of two
approaches to access h1
Summary on TMD Program
• Unprecedented precision 4-d mapping of SSA
•
Collins, Sivers, Pretzelosity and Worm-Gear
• Both polarized 3He (n) and polarized proton with SoLID
• Three “A” rated experiments approved. One LOI on di-hadron.
• Combining with the world data
•
•
•
•
•
extract transversity and fragmentation functions for both u and d quarks
determine tensor charge
study TMDs for both valence and sea quarks
learn quark orbital motion and quark orbital angular momentum
study Q2 evolution
• Global efforts (experimentalists and theorists), global analysis
• much better understanding of multi-d nucleon structure and QCD
• Welcome new collaborators
•
Longer-term future: Electron-Ion Collider to study sea and gluon TMD
EIC in China (a new possibility)
Parity Violating DIS at JLab 6 GeV
New Results (Slides by X. Zheng)
6 GeV PVDIS Results
D. Wang, …, X . Zheng, et al.
Nature, 506, 7486, 67-70 (2014)
World Knowledge on Electron-Quark Contact Interaction
Terms
Note the equal scale in
horizontal and vertical
direction. Yet data on
C2q won't fit inside the
frame.
PVDIS at 6 GeV (JLab E08-011)
Ran in Oct-Dec 2009, 100uA, 90%
polarized electron beam, 20-cm liquid
deuterium target
Scaler-based fast counting DAQ
specifically built for the 500kHz DIS
rates w/ 104 pion rejection.
Spokespeople:
P. Reimer, R. Michaels, X.Z.
Postdoc: Ramesh Subedi
Grad. Students: Kai Pan (MIT),
Xiaoyan Deng (UVa),
PhD Students: Diancheng Wang
(UVa),
With JLab E08-011 Results
Improved on C2q by
factor of five
Agree with Standard
Model
2C2u-C2d is two sigma
from zero, as predicted
by the Standard Model.
32
Parity Violating DIS at JLab 12 GeV
SoLID Program
PVDIS with SoLID
Contact Person: P. Souder
• High Luminosity on LD2 and LH2
• Better than 1% errors for small bins
over large range kinematics
• Test of Standard Model
• Quark structure:
charge symmetry violation
quark-gluon correlations
d/u at large-x
12 GeV PVDIS Sensitivity: C1 and C2 Plots
World’s data
6 GeV
PVDIS
Precision Data
Qweak
Cs
PVDIS
QCD: Charge Symmetry Violation
We already know CSV exists:
• u-d mass difference δm = md-mu ≈ 4 MeV
δM = Mn-Mp ≈ 1.3 MeV
• electromagnetic effects
• Direct observation of CSV—very exciting!
• Important implications for PDF’s
• Could be a partial explanation of the NuTeV anomaly
For APV in electron-2H DIS:
MRST PDF global with fit of CSV
Martin, Roberts, Stirling, Thorne Eur Phys J C35,
325 (04)
Broad χ2 minimum
(90% CL)
MRST (2004)
SoLID-J/y: Study Non-Perturbative Gluons
Spokespersons: K. Hafidi, Z.E. Meziani, X. Qian,
N. Sparveris and Z. Zhao
J/ψ: ideal probe of non-perturbative gluon
The high luminosity & large acceptance
capability of SoLID enables a unique
“precision” measurement near threshold
•Search for threshold enhancement
•Shed light on the conformal anomaly

G


G
Gluon
Energy
Quark
Mass
Trace
Anomaly
Quark
Energy
X. Ji PRL 74 1071 (1995)
 + N  N + J /y
*
50 days @
1037 N/cm2/s
Summary
• Nucleon TMD study have been exciting and fruitful
• Recent and Preliminary Results on TMD studies from JLab
• JLab 12 GeV : Planned SoLID program on TMDs
Precision 4-d mapping of TMD asymmetries
Precision experimental data + development in theory for Nucleon TMDs +…
 lead to breakthrough in understanding QCD?
•
•
Results from 6 GeV PVDIS
JLab 12 GeV: Solid Program on PVDIS
Low energy test of Standard Model
Precision Hadron Structure Study: Charge Symmetry Violation,
Higher-twist effect, d/u at high x
Backup Slides
Jefferson Lab at a Glance (12 GeV now! )
CEBAF
 High-intensity electron
accelerator based on CW
SRF technology
 Emax = 6 GeV 12 GeV
 Imax = 200 mA
 Polmax = 85%
A
C
B
A B C
 ~ 1400 Active Users
 ~ 800 FTEs
 178 Completed Experiments
@ 6 GeV
 Produces ~1/3 of US PhDs
in Nuclear Physics
Unpolarized and Polarized TMDs
Flavor PT Dependence
JLab Hall C/B SIDIS Results
Flavor PT Dependence from Theory
Chiral quark-soliton model (Schweitzer, Strikman, Weiss, JHEP, 1301 (2013)
 sea wider tail than valance
f1u/f1d
kT
•Flagmentation model, Matevosyan, Bentz, Cloet, Thomas, PRD85 (2012)
 unfavored pion and Kaon wider than favored pion
Hall C Results: Flavor PT Dependence
(md)2
(m-)2
(mu)2
C
(m+)2
arXiv:1003.4549
A1
A1 PT-dependence
Lattice
PT
B.Musch et al arXiv:1011.1213
CLAS data suggests that width of g1 is less than the width of f1
plots courtesy of Harut Avagyan
E06-010
3He
Target Single-Spin Asymmetry in SIDIS
X. Qian at al., PRL 107:072003(2011)
3
He-(e, e'h), h = p +, p 3He
Collins SSA small
Non-zero at highest x for p+
3He
Sivers SSA:
negative for π+,
Blue band: model (fitting) uncertainties
Red band: other systematic uncertainties
Asymmetry ALT Result
J. Huang et al., PRL. 108, 052001 (2012).
To leading twist:
cos(h s )
cos(h s )
ALT
 FLT
 g1qT  D1hq
•
3He
ALT : Positive for p-
Worm-Gear.
Inclusive Hadron Electroproduction
e + N↑
h+X
(h = p, K, p)
pT
σUT
 
  
 S N  l xPh ∼sin  S 
AN  xF , pT  = A

sin  S
UT
Why a non-zero AN is interesting?
–
–
–
–
–

Analogues to AN in pp↑ →hX collision
Simpler than pp ↑ →hX due to only one quark channel
Same transverse spin effects as SIDIS and p-p collisions (Sivers, Collins, twist-3)
Clean test TMD formalism (at large pT ~ 1 GeV or more)
To help understand mechanism behind large AN in pp↑ →hX in the TMD framework
Transverse SSA in Inclusive Hadron


 

S N  l xPh = 0
 
 S = 0
sin  S
AUT

sin  S
AUT


=

N N
N +N
p
p+
False Asymmetry
• Target spin flip every 20 minutes
• Acceptance effects cancels
• Overall systematic check with AN at ϕS= 0
– False asymmetry < 0.1%
JLab Physics Program at 12 GeV
Hall A – form factors, GPDs & TMDs , SRC
Hall A
Low-energy tests of the SM and Fund. Symmetry Exp
SoLID, MOLLER.
Hall B
High luminosity, high resolution &
dedicated equipments
Hall B - 3-D nucleon structure via GPDs & TMDs
Search new form of hadron. matter via Meson Spectr.
4p detector
Hall C – precision determination of valence quark
Hall C
properties in nucleons and nuclei
Hermetic detector
Photon tagger
high momentum spectrometers &
dedicated equipments
Hall D
Hall D - exploring origin of confinement by studying exotic
mesons using real photons
49
Multi-Halls SIDIS Program
Hall B/CLAS12
Hall A/SBS
General survey,
medium
luminosity
High x - Q2, 2-3D
Hall A/SOLID
High Lumi and
acceptance – 4D
N
q
U
L
Hall C/SHMS
L-T
precise
ratios
studies,
p+/p-
T
U
L
3He,
NH3
T
H2/D2,
NH3/ND3, HD
H2 D2
Map Collins and Sivers asymmetries in 4-D (x, z, Q2, PT)
The TMD simulation: Projections for SIDIS Asymmetry π+
EIC@HIAF
reach high
precision
similar to
SoLID at
lower x,
higher Q2
region
Haiyan Gao (Duke)
Green (Blue) Points: SoLID projections for polarized NH3 (3He/n) target
Luminosity: 1035 (1036) (1/cm2/s); Time: 120 (90) days
Black points: EIC@HIAF projections for 3 GeV e and 12 GeV p
Luminosity: 4 x 1032 /cm2/s; Time: 200 days
QCD: Higher Twist
From the Quark Parton Model (QPM) to QCD
1.Add DGLAP evolution
2.Add higher order terms in the Operator Product Expansion (OPE)↔Higher Twist Terms
Parton Model—
leading twist
Di-quarks
Quark-gluon
diagram
What is a true
quark-gluon
operator?
Quark-gluon operators
correspond to
transverse momentum
QCD equations
of motion
PVDIS on the Proton: d/u at High x
u ( x) + 0.91d ( x)
a ( x) 
u ( x) + 0.25d ( x)
P
Deuteron analysis has large
nuclear corrections (Yellow)
APV for the proton has no such
corrections
(complementary to
BONUS/MARATHON)
3-month run