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

Maintain capability to deliver lower pass beam energies : 2.2, 4.4, 6.6,….

Enhanced capabilities in existing HallsIncrease of Luminosity 1035 - ~1039 cm-2s-1

The completion of the 12 GeV Upgrade of CEBAF was ranked the highest priority in the 2007 NSAC Long Range Plan. New Hall

CHL-2

20 cryomodules

Add 5 cryomodules

Add 5 cryomodules

20 cryomodules

Add arc

Wpu(x,k

T,r ) Wigner distributions

d2kT

PDFs f1

u(x), .. h1u(x)

GPDs/IPDs

d2kTd2rT

TMD PDFs

f1u(x,kT), ..

h1u(x,kT) 3D imaging

5D Dist.

Form FactorsGE(Q2), GM(Q2)

d2rT

dx &Fourier Transformation

1D

Unified View of Nucleon Structure

Quark polarization

Unpolarized(U)

Longitudinally Polarized (L)

Transversely Polarized (T)

Nucleon Polarization

U

L

T

Leading-Twist TMD PDFs

f1 =

f 1T =

Sivers

Helicityg1 =

h1 =Transversity

h1 =

Boer-Mulders

h1T =

Pretzelosity

g1T =

Worm Gear

h1L =

Worm Gear

: Probed with transversely pol targetHERMES, COMPASS, JLab E06-010

Nucleon Spin

Quark Spin

Scattering Plane

Gold mine for TMDs Access all eight leading-twist TMDs

through spin-comb. & azimuthal-modulations

Tagging quark flavor/kinematics

Tool: Semi-inclusive DIS (SIDIS)

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 E06-010Published and Preliminary Results

From SIDIS and Inclusive Reactions

SIDIS: Separation of Collins, Sivers and pretzelocity effects through angular dependence

1( , )

sin( ) sin( )

sin(3 )

l lUT h S

h SSiverCollins

Pretzelosi

UT

tyU

sUT h S

h ST

N NA

P N

A

A

N

A

1

1 1

1

1 1

sin( )

sin(3 )

sin( )Co

PretzelosityU

SiversUT

llins

T h S T

h S

UT

UT h S

TU

UT

TA

H

f

A

D

A h H

h

E06 010 Experiment‑

• First measurement on n (3He)• Transversely Polarized 3He Target• Polarized Electron Beam, 5.9 GeV

• 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

9

Beam Polarimetry(Møller + Compton)

LuminosityMonitor

XKeeHe ),(3 Spokespersons: J. P. Chen, E. Cisbani, H. Gao, X. Jiang and J. C. Peng 7 PhD Thesis Students (graduated) + 2 new students

3He (n) Target Single-Spin Asymmetry in SIDIS

,),',(n hhee

neutron Sivers SSA:negative for π+, Agree with Torino Fit

neutron Collins SSA small Non-zero at highest x for p+

Blue band: model (fitting) uncertainties Red band: other systematic uncertainties

E06-010 collaboration, X. Qian at al., PRL 107:072003(2011)

Asymmetry ALT Result

• neutron ALT : Positive for p- • Consist w/ model in signs, suggest larger asymmetry

hq

qTLT DgFA shsh

11)cos()cos(

LT

To leading twist:

J. Huang et al., PRL. 108, 052001 (2012).

Worm-Gear

Dominated by L=0 (S) and L=1 (P) interference

Trans helicity

Pretzelosity Results on Neutron

Extracted Pretzelosity Asymmetries,

New Results

In models, directly related to OAM,L=0 and L=2 interference

Analysis by Y. Zhang (Lanzhou) and X. Qian (Caltech)

submitted to PRC, arXiv:1312.3047

E06-010: Inclusive Hadron SSA (AN)

• Clear non-zero vertical target SSA

• Opposite sign for p+ and p-

• Large for K+

0 hN PxlS

0sin90=A S

SUT

vertical target

ShNUT PxlSσ sin∼

Analysis by K, Allada (JLab), Y. Zhao (USTC),

PRC 89, 042201 (2014)

E06-010: Inclusive Hadron SSA (AN)

• Clear non-zero target SSA

• Opposite sign for p+ and p-

• AN at low p

T not very well

understood• Results consistent with

predictions based on Sivers mechanism (valid at high pT )

0 hN PxlS

0sin90=A S

SUT

vertical target

Inclusive Target Single Spin Asymmetry: DIS

3Heθ

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.

Ay (Q2)

• In DIS case: related to integral of Sivers• Physics Importance discussed in A. Metz’s paper

Inclusive Target Single-Spin Asymmetry

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)

Analysis by J. Katech(W&M), X. Qian (Caltech), submitted to PRL, arXiv:1311.0197

Future: TMD study 12 GeV JLab

Precision Study of TMDsIn 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

• Significant Improvement in the valence quark (high-x) region• Illustrated in a model fit (from A. Prokudin)

f 1T =

E12-11-107: Worm-gear functions (A rating )Spokespersons: J. P. Chen, J. Huang, Y. Qiang and W. Yan

• 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 =

g1T =

Longi-transversityTrans-helicity

Cent

er o

f poi

nts:

)()(~ 11 zDxgA TLT )()(~ 11 zHxhA LUL

Access transversity in transversely polarized neutron target through π+ π- di-hadron production

Run simultaneously with SIDIS 3He (e,e’π±)X

Systematical check of two approaches to access h1

New : LOI – Dihadron in DIS on 3HeSpokespersons: J. P. Chen, A. Courtoy, H. Gao and J. Zhang

Asymmetry projection for one M-z bin

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 SoLIDContact 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

Cs

PVDIS

Qweak PVDIS

World’s data

Precision Data

6 GeV

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:

Broad χ2 minimum

(90% CL)

MRST PDF global with fit of CSVMartin, Roberts, Stirling, Thorne Eur Phys J C35,

325 (04)

MRST (2004)

SoLID-J/y: Study Non-Perturbative Gluons

Quark Energy

Trace Anomaly

Gluon Energy

Quark Mass

50 days @ 1037 N/cm2/s

* /N N J

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

X. Ji PRL 74 1071 (1995)

Spokespersons: K. Hafidi, Z.E. Meziani, X. Qian, N. Sparveris and Z. Zhao

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 asymmetriesPrecision 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! )

~ 1400 Active Users ~ 800 FTEs 178 Completed Experiments

@ 6 GeV Produces ~1/3 of US PhDs

in Nuclear Physics A B C

CEBAF High-intensity electron

accelerator based on CW SRF technology

Emax = 6 GeV Imax = 200 mA Polmax = 85%

A B C

12 GeV

Unpolarized and Polarized TMDsFlavor 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

• Flagmentation model, Matevosyan, Bentz, Cloet, Thomas, PRD85 (2012) unfavored pion and Kaon wider than favored pion

f1u/f1d

kT

Hall C Results: Flavor PT Dependence

C

(md)2

(mu

)2

(m-)2

(m+)2

A1 PT-dependence

CLAS data suggests that width of g1 is less than the width of f1

Lattice

PT

arXiv:1003.4549 A

1

B.Musch et al arXiv:1011.1213

plots courtesy of Harut Avagyan

E06-010 3He Target Single-Spin Asymmetry in SIDIS

3He Sivers SSA:negative for π+,

3He Collins SSA small Non-zero at highest x for p+

Blue band: model (fitting) uncertainties Red band: other systematic uncertainties

X. Qian at al., PRL 107:072003(2011)

Asymmetry ALT Result

• 3He ALT : Positive for p-

hq

qTLT DgFA shsh

11)cos()cos(

LT

To leading twist:

J. Huang et al., PRL. 108, 052001 (2012).

Worm-Gear.

Inclusive Hadron Electroproduction

e + N↑ h + X (h = p, K, p)

Why a non-zero AN

is interesting?

– Analogues to AN in collision

– Simpler than 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 p

T ~ 1 GeV or more)

– To help understand mechanism behind large AN in in the TMD framework

pT

pp↑→hX

Ssin

UTTFN A=p,xA

pp↑→ hX

pp↑→ hX

ShNUT PxlSσ sin∼

Transverse SSA in Inclusive Hadron

• Target spin flip every 20 minutes• Acceptance effects cancels • Overall systematic check with A

N at ϕ

S= 0

– False asymmetry < 0.1%

0sin

=A SS

UT

N+N

NN=A S

UT

sinp+ p-

False Asymmetry

0=PxlS hN

JLab Physics Program at 12 GeV

49

Hall C – precision determination of valence quark properties in nucleons and nuclei

high momentum spectrometers & dedicated equipments

Hall B - 3-D nucleon structure via GPDs & TMDs Search new form of hadron. matter via Meson Spectr.

4p detector

Hall A – form factors, GPDs & TMDs , SRCLow-energy tests of the SM and Fund. Symmetry Exp

SoLID, MOLLER.

High luminosity, high resolution & dedicated equipments

Hall D - exploring origin of confinement by studying exotic mesons using real photons

Hermetic detectorPhoton tagger

Hall A

Hall B

Hall C

Hall D

H2 D2

Hall C/SHMSL-T studies, precise p+/p- ratios

Hall C/SHMSL-T studies, precise p+/p- ratios

3He, NH3

Hall A/SBSHigh x - Q2, 2-3D

Hall A/SBSHigh x - Q2, 2-3D

Hall A/SOLIDHigh Lumi and acceptance – 4D

Hall A/SOLIDHigh Lumi and acceptance – 4D

U L TqN

U

L

T H2/D2,NH3/ND3, HD

Hall B/CLAS12General survey, medium luminosity

Hall B/CLAS12General survey, medium luminosity

Multi-Halls SIDIS Program

Map Collins and Sivers asymmetries in 4-D (x, z, Q2, PT)

Green (Blue) Points: SoLID projections for polarized NH3 (3He/n) targetLuminosity: 1035 (1036) (1/cm2/s); Time: 120 (90) days

Black points: EIC@HIAF projections for 3 GeV e and 12 GeV pLuminosity: 4 x 1032 /cm2/s; Time: 200 days

The TMD simulation: Projections for SIDIS Asymmetry π+

Haiyan Gao (Duke)

EIC@HIAF reach high precision similar to SoLID at lower x, higher Q2 region

QCD: Higher Twist

From the Quark Parton Model (QPM) to QCD1.Add DGLAP evolution2.Add higher order terms in the Operator Product Expansion (OPE)↔Higher Twist Terms

Parton Model—leading twist

Di-quarks

Quark-gluondiagram

What is a truequark-gluonoperator?

Quark-gluon operatorscorrespond to

transverse momentum

QCD equationsof motion

PVDIS on the Proton: d/u at High x

Deuteron analysis has largenuclear corrections (Yellow)

APV for the proton has no such corrections

(complementary to BONUS/MARATHON)

)(25.0)(

)(91.0)()(

xdxu

xdxuxaP

3-month run