Hall A Collaboration Meeting 1

TMD Physics with SoLID-SIDIS

Xin Qian

Caltech

For the SoLID-Spin Collaboration

A Unified Picture of Nucleon Structure Wp

u(x,kT,r ) Wigner distributions

PDFs f1

u(x), .. h1u(x)

d2kT

d3r

TMD PDFs f1

u(x,kT), .. h1u(x,kT)

X. Ji PRL 91 (03)

3D imaging

6D Des.

Form FactorsGE(Q2), GM(Q2)

GPDs/IPDs

d2kT drz

d2rT

dx &Fourier Transformation

1D2

Nucleon Spin Structure• Understand Nucleon Spin in terms of quarks

and gluons (QCD)

– Small contribution from quarks and gluons’ intrinsic spin

~30% from data “spin crisis”

Nucleon’s spinJi’s Sum Rule

J q

Orbital angular momentum is important!Parton transverse motion + Spin-orbit correlations

Hall A Collaboration Meeting 3

Hall A Collaboration Meeting 4

Transverse Momentum Dependent PDFs

TMD

Nucleon Spin

QCD Dynamics

Quark OAM/Spin

QCD Factorization

3-D Tomography

Lattice QCD

Models

TMD f1u(x,kT)

Longitudinal Direction zTransverse

Plane x-y

Quark polarization

Unpolarized(U)

Longitudinally Polarized (L)

Transversely Polarized (T)

Nucleon Polarization

U

L

T

Leading-Twist TMD PDFs

f1 =

f 1T =

Sivers

Helicity

g1 =

h1 =Transversity

h1 =

Boer-Mulders

h1T =

Pretzelosity

g1T =

Worm Gear

h1L =

Worm Gear(Kotzinian-Mulders)

Nucleon Spin

Quark Spin

Spin-orbital (trans. mom.) correlation is important!

Very well known

Reasonably known

Hall A Collaboration Meeting 5

Hall A Collaboration Meeting 6

Access TMDs through Semi-Inclusive DIS

...]})cos(1[

...]1[

...])3sin(

...)()sin(

)sin([

...])2sin([

...)2cos(

...{

)1(2

)cos(2

2

)3sin(

)sin(

)sin(

)2sin(

)2cos(

,

2

2

2

2

Sh

Sh

Sh

Sh

h

h

LTSheT

LLeL

UTSh

ULSh

UTShT

ULhL

UUh

TUU

hhS

FS

FS

F

F

FS

FS

F

F

y

xyQdPdzddxdyd

d

Unpolarized

PolarizedTarget

PolarizedBeam andTarget

Boer-Mulder

Sivers

Transversity

Pretzelosity

f1 =

f 1T =

g1 =

g1T =

h1 =

h1L =

h1T =

h1T =

SL, ST: Target Polarization; le: Beam Polarization

Semi-Inclusive DIS

Parton distribution function (PDF)

Fragmentationfunction (FF)

DXs ~ PDF X FFh tags struck quark’s flavor, spin and transverse momentum

Current Fragmentation

h

XhkPk '

Hall A Collaboration Meeting 7

1( , )

sin( )

sin( )

sin(3 )

l lUT h S

h S

Siver

Collins

Pretzelosi

UT

tyU

sUT h S

h ST

N NA

P N

A

A

N

A

Hall A Collaboration Meeting 8

Hall A Polarized 3He Target

~90% ~1.5% ~8%

S S’ D

High luminosity: L(n) = 1036 cm-2 s-1 20 mins spin flip with K/Rb hybrid cells ~55% in beam polarization

Polarized Laser795 nm

25 G Holding Field

Oven 230 oC

F = 3”Pumping Chamber

40 cm Target Chamber

1o atm 3HeSome N2, Rb, K

favunfavn

unfavfavn

DuDd

DuDd

24

24

)( du )( du

Collins effect

• Access to transversity– Transversity links

quak’s spin tonucleon spin

– Collins FF links quark’s spin to hadron transverse momentum

• Artru model– Based on LUND

fragmentation picture.

Hall A Collaboration Meeting

11 HhA TCollins

9

Rich Physics in TMDs (Sivers Function)• Correlation between nucleon spin with quark

orbital angular momentum

Burkhardt : chromodynamic lensing

Final-State-InteractionYD

qTSIDIS

qT ff

11Important test forFactorization

11 DfA TSivers

Hall A Collaboration Meeting 10

Hall A Collaboration Meeting 11

Results on Neutron• Sizable Collins π+

asymmetries at x=0.34?– Sign of violation of

Soffer’s inequality?– Data are limited by

stat Needs more precise data!

• Negative Sivers π+

Asymmetry– Consistent with

HERMES/COMPASS– Independent

demonstration of negative d quark Sivers function.

Model (fitting) uncertainties shown in blue bandRadiative correction, diffractive ρ production, and finalize systematic uncertainties before submission

X. Qian PRL 107 072003 (2011)

Hall A Collaboration Meeting 12

• – Leading twist TMD PDFs– T-even, Chiral-even

• Dominated by real part of interference between L=0 (S) and L=1 (P) states– Imaginary part -> Sivers effect

• First TMDs in Lattice calculation– arXiv:0908.1283 [hep-lat],Europhys.Lett.88:61001,2009– arXiv:1011.1213 [hep-lat] , Phys.Rev.D83:094507,2011

Double Spin Asymmetry: g1T

Worm Gear

g1T =

TOT

g1T (1)

S-P int.

P-D int.

Light-Cone CQM by B. Pasquini B.P., Cazzaniga, Boffi, PRD78, 2008Target

Spin

BeamHelicity

e

e’

π

X

n

hq

qT DgA sh

11)cos(

LT

Hall A Collaboration Meeting 13

Extract Neutron ALThq

qT

n DgA 11LT

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

• Neutron π+ data is sensitive to d , π- data also sensitive to u• Consist w/ model in signs, suggest larger asymmetry

Hall A Collaboration Meeting 14

SoLID-Spin: SIDIS on 3He/Proton @ 11 GeV

E12-10-006: Single Spin Asymmetry on Transverse 3He @ 90 days

E12-11-007: Single and Double Spin Asymmetry on 3He @ 35 days

E12-11-108: Single and Double Spin Asymmetries on Transverse Proton @ 120 days

Key of SoLID-Spin program: Large Acceptance + High Luminosity4-D mapping of asymmetriesTensor charge, TMDs …Lattice QCD, QCD Dynamics, Models

White paper: Eur. Phys. J. Plus (2011) 126:2

SoLID Setup for SIDIS• Tracking: GEM Tracker.

– Shared R&D with Super BigBite

• Electron Identification:– Large angle

• E&M calorimeter

– Forward angle• E&M calorimeter • Light gas Cerenkov

• Pion identification:– Heavy Gas Cerenkov– TOF (Multi-gap Resistive

Plate Chamber) 15Hall A Collaboration Meeting

• Fast pipeline DAQ (Similar to Hall D)

• Polarized 3He and Polarized NH3 targets

16

Projections on Collins/Sivers Asymmetry (90 Days)

Collins 1/48 bins4-D Mapping of AsymmetriesTensor Charge

Hall A Collaboration Meeting

Sivers 1/48 bins

Expected Improvement of Sivers Function

From A. Prokudin

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Requirement of SIDIS• Kinematics Coverage:

– 0.05 ~ 0.6 in x (valence)– 0.3 ~ 0.7 in z (factorization

region)

– PT up to ~ 1 GeV (TMD Physics)

– Fixed target Q2 coverage 1-8 GeV2 (~ 2 GeV2 in ΔQ2 at fixed x)

• Luminoisity:– Unpolarized ~ 1037 N/cm2/s

• Polarized 3He Target:– ~ 60% higher polarization– Fast spin flip (<20 mins)

• Electron PID:– <1% Pion contamination

(asymmetry point of view)

• Pion PID:– <1% Kaons and Protons– <1% electron contamination

• Optics of Reconstruction:– < a few % in δP/P.– < 1 mr in polar angle.– < 10 mr in azimuthal angle – ~ 1-2 cm vertex resolution– Similar precision required.– A factor of 2-3 better already

achieved in MC.

• DAQ:– ~ 3kHz Physics Coincidence– ~ 100 kHz Single electron– ~ 60 kHz Coincidence– Limits: 300 MB/s to tape.

• Electron Ion Collider: – The Next QCD Frontier - Understanding the glue

that binds us all (arXiv:1212.1701)

• Stage-I EIC– Proton Spin– The motion of quarks and

gluons in the proton• Sea quark TMDs Gluon Sivers? • Test Collins-Soper Evolution at large x

– The tomographic images of the proton– QCD matter at an extreme gluon density– Quark hadronization

Bright Future for TMDs

18Hall A Collaboration Meeting

Hall A Collaboration Meeting 19

Impact of Jlab12 + EIC

Hall A Collaboration Meeting 20

Summary• TMD physics plays a crucial role in

understanding Nucleon Spin/Quark OAM

• Neutron SSA and DSA has been measured for the first time in Hall A

• TMD physics with SoLID-SIDIS– u/d tensor charge measurements– 4-D measurements in the valence region

• Natural extensions at future EIC