Jefferson Lab E06-010 CollaborationInstitutions

CMU, Cal-State LA, Duke, Florida International, Hampton, UIUC, JLab, Kharkov, Kentucky, Kent State, Kyungpook National South Korea, LANL, Lanzhou Univ. China, Longwood Univ. Umass, Mississippi State, MIT, UNH, ODU, Rutgers, Syracuse, Temple, UVa, William & Mary, Univ. Sciences & Tech China, Inst. of Atomic Energy China, Seoul National South Korea, Glasgow, INFN Roma and Univ. Bari Italy, Univ. Blaise Pascal France, Univ. of Ljubljana Slovenia, Yerevan Physics Institute Armenia.

Collaboration members K. Allada, K. Aniol, J.R.M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P.C. Bradshaw, P.

Bosted, A. Camsonne, M. Canan, G.D. Cates, C. Chen, , J.-P. Chen (Co-SP), W. Chen, K. Chirapatpimol, E. Chudakov, , E. Cisbani(Co-SP), J. C. Cornejo, F. Cusanno, M. M. Dalton, W. Deconinck, P.A.M. Dolph , C. de Jager, R. De Leo, X. Deng, A. Deur, H. Ding, C. Dutta, C. Dutta, D. Dutta, L. El Fassi, S. Frullani, H. Gao(Co-SP), F. Garibaldi, D. Gaskell, S. Gilad, R. Gilman, O. Glamazdin, S. Golge, L. Guo, D. Hamilton, O. Hansen, D.W. Higinbotham, T. Holmstrom, J. Huang, M. Huang, H. Ibrahim, M. Iodice, X. Jiang (Co-SP), G. Jin, M. Jones, J. Katich, A. Kelleher, A. Kolarkar, W. Korsch, J.J. LeRose, X. Li, Y. Li, R. Lindgren, N. Liyanage, E. Long, H.-J. Lu, D.J. Margaziotis, P. Markowitz, S. Marrone, D. McNulty, Z.-E. Meziani, R. Michaels, B. Moffit, C. Munoz Camacho, S. Nanda, A. Narayan, V. Nelyubin, B. Norum, Y. Oh, M. Osipenko, D. Parno, , J. C. Peng(Co-SP), S. K. Phillips, M. Posik, A. Puckett, X. Qian, Y. Qiang, A. Rakhman, R. Ransome, S. Riordan, A. Saha, B. Sawatzky,E. Schulte, A. Shahinyan, M. Shabestari, S. Sirca, S. Stepanyan, R. Subedi, V. Sulkosky, L.-G. Tang, A. Tobias, G.M. Urciuoli, I. Vilardi, K. Wang, Y. Wang, B. Wojtsekhowski, X. Yan, H. Yao, Y. Ye, Z. Ye, L. Yuan, X. Zhan, Y. Zhang, Y.-W. Zhang, B. Zhao, X. Zheng, L. Zhu, X. Zhu, X. Zong.

Neutron Transversity: Current Status and the Future

Xin Qian Kellogg Radiation Lab

Caltech

Transverse Momentum Dependent

PDFs

TMD

Nucleon Spin

QCD Dynam

ics

Quark OAM/Spin

QCD Factoriz

ation

3-D Tomography

Lattice QCD

Models

TMD f1

u(x,kT)

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(Kotzinian-Mulders)

: Survive trans. momentum integration

Nucleon Spin

Quark Spin

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 NAP N

A

ANA

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

N

q q

N

Helicity state

Rich Physics in TMDs (Transversity)

Some characteristics of transversity h1T = g1L for non-relativistic quarks No gluon transversity in nucleon Soffer’s bound

|h1T| <= (f1+g1L)/2 Violation of Soffer bound due to QCD confiment? J. P. Ralston arxiv:0810.0871

Chiral-odd → difficult to access in inclusive DIS Tensor Charge: Integration of transversity over x.

Calculable in LQCD

Parton Distributions (CTEQ6)

(Torino)

Unpolarized

Helicity

Transversity

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

Experiments on polarized ``neutron’’ urgently needed!!

)92()

94()

91()

91()

94(

)91()

98()

91()

94()

94(

..

pp

SC

nnn

ppppp

uddduN

duduuP

u quark dominated

Sensitive to d quark

)( du )( du

duudunfav

uddufav

DDDDD

DDDDD

favunfavn

unfavfavn

DuDd

DuDd

24

24

Sensitive to d quarkSensitive to u quark

E06-010 Setup• Electron beam: E = 5.9 GeV• 40 cm transversely polarized 3He • BigBite at 30o as electron arm:

Pe = 0.6 ~ 2.5 GeV/c• HRSL at 16o as hadron arm:

Ph = 2.35 GeV/c• Average beam current 12 uA (15

uA in proposal)• Average 3He polarization is ~55%.

(42% in proposal)

e

Polarized3He Target

HRSL

16o

g*

e’

BigBite30o

Two large installation Devices: 3He target + BigBite Spectrometer.

Why Polarized 3He Target ?

Effective Polarized Neutron Target!

~90% ~1.5% ~8%

S S’ D

High luminosity: L(n) = 1036 cm-2 s-1 20 mins spin exchange with K/Rb hybrid cells

Pioneer studies performed at KRL

Reached a steady 60% polarization with 15 mA beam and 20 minute spin flip! A NEW RECORD!

Thanks to the hard work of the entire target group!

High Resolution Spectrometer• Left HRS to detect hadrons of

ph = 2.35 GeV/c• Gas Cherenkov + VDC +

Scintillator +Lead-glass detectors

• Aerogel Cherenkov counter– n = 1.015

• RICH detector– n = 1.30

• Kaon detection:– A1: Pion rejection > 90 %– RICH: K/ separation ~ 4 – TOF: K/ separation ~ 4

e Coincidence Time

< 400 ps

K

p

K

4 σ Separation Cherenkov Ring From RICH

Electron Arm: BigBite

• Wire Chamber Tracking• Shower system and Gas

Cerenkov for electron PID.

Wire chamber

Gas Cerenkov

Shower system

ScintillatorMagnetic field shielding

OpticsSlot-slit

• 64 msr• large out-of-plane

acceptance, essential for separating Collins/Sivers effect

BigBite Optics• Multi-Carbon Target for vertex reconstruction• Sieve Slot for angular reconstruction • Hydrogen elastic scattering at 1.2 GeV and 2.4

GeV for momentum reconstruction• Also positive optics

BigBite Sieve Slit

Contamination (Photon-Induced Electron)• πo induced electrons:

– Direct Decay to γe+e-

– γ interacted with material, pair production

– Same kinematics for e+ and e-

• Single:– Method I: (e+ Data Directly)– Method II: MC

• Coincidence channel:– Ratio method, – Direct from e+ Data

• Consistent with Hall B/C Data

Single

Coincidence

X-bin 1 2 3 4

π+ 21% 8% 2.4% 1.0%

π- 24% 14% 5% 2.0%

Uncer. Rel. 20% 25% 35% 50%

3He Results

After correction of N2 dilution (dedicated reference cell data)Model (fitting) uncertainties are shown in blue band.Other systematic uncertainties shown in red band.

Non-zero Collins moments at highest x bin for π + (2.3 σ stat. + sys. + mod.)

Favor a negative values for Sivers π + results.

Comparison with World Data

Proton Dilution

He

pHen

p

n

pnHe

ppnnHe

f

p

p

pp

3

3

9.04.0

6.32

3

3

2

%8.2

%86

2

2

Effective Polarization ApproachPlane Wave Approximation

fn measured with dedicated data. Corrected by Proton Asymmetries. Nuclear effect ISI under control: S. Scopetta PRD75 054005 (2007)Unpolarized FSI: <3.5% from multiplicity measurementSpin-dependent FSI were estimated to be well below 1% within a simple Glauber rescattering model

nn

ppnHen Pf

APfAA

)1(3

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 band.Radiative correction: bin migration + uncer. of asy.Spin-dependent FSI estimated <1% (Glauber rescattering + no correction) Diffractive rho: 3-10%

Best Measurements on Neutron at High x

Paper Appeared on arXiv• arXiv: 1106.0363, will submit in a few days.

Experimental Overview• SoLID (proposed for PVDIS) 3He(e,e’π+/-)– Large acceptance: ~100 msr for polarized (without baffles)– High luminosity

• High pressure polarized 3He target – SIDIS: improve by a factor of 100-1000

• 11 GeV beam,15 µA (unpolarized/polarized)• Unpolarized H/D/3He factorization test & dilution corrections

• Two approved experiments: E10-006 & E11-007– SSA in SIDIS Pion Production on a Transversely/ Longitudinally

Polarized 3He Target at 8.8 and 11 GeV. • White paper: H. Gao et al. Eur. Phys. J. Plus 126:2 (2011)

• Also SBS Transversity Program focus on high Q2.

SoLID Setup for SIDIS on 3He• Shared device with

PVDIS:– GEM Tracker– Light Gas Cerenkov– Calorimeter

• Shared R&D in– GEM– Light collection in

magnetic field.– Fast DAQ– New Calorimeter

System

Additional devices of MRPC, scintillator plane, heavy gas Cerenkov which provide us the capability in hadron detection.

Projections (1 of 48 bins 0.3<z<0.7)

11)sin( HhA TshCollinsUT

Selected Physics Motivation

• 10% measurement of d quark transversity– Test of Soffers bound at high x

• Search for sign change in Sivers function– Measure Sivers function at high PT

– Data at high x low Q2 for evolution studies– Precision data to test

• First non-zero measurement of Pretzlosity• DSA: Worm-gear functions– Test model calculations > ‐ h1L =? ‐g1T

– Connections with Collinear PDFs through WW approx. and LIR.

YD

qTSIDIS

qT ff

11

Bright Future for TMDs• Golden channel of Electron-

Ion Collider

Dream!

TMDs at EIC• Sea quark TMDs, what will happen at very low x?• Gluon Sivers through back-to-back D-meson production• Twist-3 tri-gluon correlation through D-meson

production• TSSA at medium/large PT Twist-3 approach vs. TMDs• Test Collins-Soper Evolution for high vs. low Q2 at large

x.

• See more discussion in Duke EIC-TMD workshop summary:– M. Anselmino et al. arxiv:1101.4199 EPJ A47,35 2011.

Summary Measuring Transversity and TMDs through SIDIS open a

new window to understand nucleon (spin) structure. First Direct Neutron SSA @ E06-010

Best neutron results in the valence quark region. “Interesting behavior” of d transversity at large x. Independently confirmation of negative d quark

Sivers function.

Transversity and TMDs: from exploration to precision JLab 12 GeV energy upgrade: an ideal tool for this study

A large acceptance SoLID with high luminosity 3He target TMD: sea quark, gluon, evolution studies TMD vs. twist-3

collinear pdf at large PT @ EIC

BigBite Wire Chamber• Three Chambers, 6 planes each, 200 wires

each plane: more than 3000 wires in total.– Connecting/Debuging/Understanding

• Special thanks to Brandon Craver and Seamus Riordan

• Monitor the hit efficiency• Offline calibration: residual σ ~ 180 um– Time Offset Calibration– Drift Time to Drift Distance conversion– Wire Position – Iteration procedure with help of tracking

Understanding BigBite Tracking• Tracking: Pattern match tree search (Ole)• Online: Low luminosity + Event Display– use elastic electron events (high energy deposition

in calorimeter): >85%– Tracking efficiency vs. luminosity

• Offline: – BigBite GEANT3 Simulation (Comgeant) >95%– 1st pass hydrogen

elastic cross section measurement ~95%

Check of BigBite Optics• Different combination of sieve/target• Sieve runs at 5th pass, carbon foils run at 5th pass• 5th pass hydrogen elastic to check the behavior at

high momentum

Data Quality Check• A good data sample is a key for the success of

data analysis– Low level checks on detector responses on different

detectors• E.g. PMT responses of Gas Cerenkov

– Low level checks on trigger rates/DAQ live times• Identified problems as Q1 quenching• Occasions with DAQ problems

– Careful catalog of all the runs• Web-based Run list (PHP-MYSQL)

– More than one month dedicated time in this work.

Fun with Data Taking• Special thanks to our spokespersons for giving

us a lot of freedom in playing with our system.– Understand the timing and trigger circuit ->

Creation of BigBite retiming circuit + firmly establish all the delays

– Understanding the distribution/background -> BigBite Positive polarity run

– During Janurary run: four problems (Gas Cerenkov spectrum, live time, Helicity signals, Left arm EDTP signal) gradually happened -> a loose L1A cable in the left HRS

Rich Physics Topics

• Pion Collins/Sivers SSA Moments• DSA Moments with polarized beam• Results on Kaons/Protons– Observation of anti-proton

• DIS Ay (inclusive, also g2)• Large asymmetries on inclusive hadron.• …