Prospects in neutron transverse spin study with a polarized 3He Target at 12 GeV JLabHaiyan Gao ()Duke University/TUNLDurham, NC, U.S.A. A Third Joint meeting of Division of Nuclear Physics of American Physical Society and the Japanese Physical Society Oct 13-17, 2009 Waikaloa, Hawaii(

OutlineIntroductionFirst experiment at 6 GeV in Hall A @ JLab (Xiaodong Jiang)Transversity with 12 GeV at JLab Summary

QCD Nucleon StructureStrong interaction, running coupling ~1 -- QCD: the theory of strong interaction -- asymptotic freedom (2004 Nobel) pQCD works at high energy -- interaction significant at intermediate energy quark-gluon correlations -- confinement interaction strong at low energy coherent hadron -- Chiral symmetry -- theoretical tools: pQCD, OPE, Lattice QCD, ChPTE Charge and magnetism (current) distributionNucleon: Electric GE and magnetic GM form factorSpin distribution Quark momentum and flavor distributionPolarizabilitiesStrangeness content..

Leading-Twist Quark Distributions non-vanishing integrating over K - dependent, T-oddK - dependent, T-even( Eight parton distributions functions)Transversity:

TransversityThree twist-2 quark distributions:Momentum distributions: q(x,Q2) = q(x) + q(x)Longitudinal spin distributions: q(x,Q2) = q(x) - q(x)Transversity distributions: q(x,Q2) = q(x) - q(x)Some characteristics of transversity:q(x) = q(x) for non-relativistic quarksq and gluons do not mix Q2-evolution simplerChiral-odd not accessible in inclusive DISRapidly developing field, worldwide efforts: BNL, Belle at KEK, CERN, DESY, JLab, FAIR project at GSI, It takes two chiral-odd objects to measure transversity

Access Parton Distributions through Semi-Inclusive DISUnpolarizedPolarizedTargetPolarizedBeam andTargetSL, ST: Target Polarization; e: Beam PolarizationBoer-MulderSiversTransversityPretzelosity

Separation of Collins, Sivers and pretzelocity effects through angular dependence

AUTsin() from transv. pol. H target Simultaneous fit to sin( + s) and sin( - s) `Collins moments Non-zero Collins asymmetry Assume q(x) from model, then H1_unfav ~ -H1_fav H1 (BELLE) (arXiv:0805:2975) `Sivers momentsSivers function nonzero (+) orbital angular momentum of quarks

Regular flagmentation functionsM. Anselmino et al, PRD75,05032(2007)

Latest Results on Sivers From HERMES arXiv:0906.3918Positive Sivers amplitudeFor ~zero for ~zero from COMPASS data On D targetNegative SiversFor u quark andPositive for d quark

Sivers asymmetries from COMPASS deuteron

Collins asymmetries from COMPASS deuteronPhys. Lett. B 673 (2009) 127-135

Transverse Target SSA Measurement at Jefferson Lab Hall A Using a Polarized 3He Target (Neutron) First Experiment Completed Recently! Experiments on polarized ``neutron important!!Jefferson Lab Hall A E06-010/E06-011

Jefferson Lab E06-010: Single Target-Spin Asymmetry in Semi-Inclusive n(e, ep) Reaction on a Transversely Polarized 3He TargetPerformed in Jefferson Lab Hall A from 10/24/08-2/6/09Exceeded the approved goal7 PhD studentsFirst measurement of the neutron Collins and Sivers asymmetries x = 0.1 - 0.4Upgraded polarized 3He target 20 min fast spin-flip vertical polarization improved performanceBigBite for e and HRSL for p and K.BigBite detectors working wellCommissioned RICH in HRSL

Nucleon Transversity at 11 GeV Using a Polarized 3He Target and SOLid in Hall A

((Hall A Collaboration proposal)Beijing U., CalState-LA, CIAE, W&M, Duke, FIU, Hampton, Huangshan U., Cagliari U. and INFN, INFN-Bari and U. of Bari, INFN-Frascati, INFN-Pavia,Torino U. and INFN, JLab, JSI (Slovenia), Lanzhou U, LBNL, Longwood U, LANL, MIT, Miss. State, New Mexico, ODU, Penn State at Berks, Rutgers, Seoul Nat. U., St. Marys, Syracuse, Tel aviv, Temple, Tsinghua U, UConn, Glasgow, UIUC, Kentucky, Maryland, UMass, New Hampshire, USTC, UVa and the Hall A Collaboration Strong theory support, Over 130 collaborators, 40 institutions, 8 countries including all 6 GeV transversity collaboration

Solenoid detector for SIDIS at 11 GeV GEMs(study done with Babar magnet, 1.5T)

Experimental OverviewSoLID (proposed for PVDIS) GEMs (tracking+vertex), Calorimeter (trigger/pid), CO2 gas cerenkov, aerogel (trigger/pid)Heavy gas cerenkov (pid)Scintillator (trigger)KinematicsForward angle region (8.5o 16o) (electron and pion)Large angle region (16o 25o) (electron only)High pressure polarized 3He target 10 amags, 40 cm long, 60% polarization, spin flip11 GeV beam,15 A (unpolarized/polarized) 8 GeVPolarized luminosity 1036/(cm2s)Unpolarized H/D/3He factorization test & dilution corrections

GEMs: tracking device6 GEMs in total: positioned inside magnet (momentum, angle and vertex reconstruction);Forward angle: 8.5o to 16o (5 layers of GEM)Large angle: 16o to 25o to (4 layers GEM, 3 in common with Forward angle)GEANT3 simulations show background rates in GEMs much less than the limit

Particle identificationElectron identificationForward angle: CO2 gas Cerenkov/EM calorimeter2 m long, 1 atm CO2,,,threshold for pion 4.8 GeV/cShower plus Cerenkov provides better than 104:1 for pion rejection for 1.5 to 4.8 GeV/c momentum region200:1 for pion rejection for momentum greater than 4.8 GeV/c (pion/e ratio < 1.5)Multi-bounce mirror system for CO2 Cerenkov counterLarge angleElectron momentum 4-6 GeV/c, expected pion/e ratio < 1.5``Shashlyk''-type calorimeter, pion rejection 200:1, efficiency for electron detection 99%

Electromagnetic Calorimeter

Pion rejection factor 200:1 for E> 2.0 GeV

Pion identificationCombination of 1 atm CO2Cerenkov, a heavy gas Cerenkov, and an aerogelCerenkov can reduce kaonBackground to < 1%

Kinematic coverage at 11 GeV

Kinematic coverage at 8 and 11 GeV

Azimuthal angular coverageFull spin angle coverage with a solenoid detection systemLarge coverage for Collins, Sivers and Pretzelosity angleImportant in disentangle all three termsSymmetry in azimuthal angular acceptance can help reduce systematic uncertainties significantly With full azimuzhal coverageSimultaneously measuredBetter control of systematic error1, 2 refer to two differentTarget spin directions in the lab

AcceptanceIncident beam energy 11 GeV

Resolutions

Rates Incident beam energy 11 GeV

Projected results (ultimate precision in SSA)7 more bins in zIncident beam energy 11 GeV, 8 GeV projection and updates soon

Positive pionsNegative pions

Power of SOLid

Trigger and DAQOption 1: Single electron rate ~ 110 kHzElectron trigger: ECAL + GC + SCDAQ will use the CODA3 and the pipeline technique being developed for Hall DExpect zero dead time with 100 200 kHz trigger rate. Option 2: Coincidence rate ~ 90 kHzPion trigger: ECAL + Aerogel + SCMulti-DAQs to reduce trigger rate in each DAQ.Will introduce some dead time. Need further studies

Systematic UncertaintiesAverage Stat: 1.8e-3, Collins asymmetry ~2%

ResponsibilitiesAerogel Cerenkov detector: Duke, UIUCCO2 gas Cerenkov detector: Temple U.Heavy Gas Cerenkov Temple U.ECal: W&M, UMass, JLab, Rutgers, SyracuseGEM detectors:UVa, Miss State, W&M, Chinese Collaboration (CIAE, HuangshanU, PKU, LZU, Tsinghua, USTC), UKY, Korean Collaboration (Seoul National U)Scintillator: Chinese Collaboration, DukeElectronics: JLabDAQ: LANL, UVa and JLabMagnet: JLab and UMassSimulation: JLab and Duke PAC decision: Defer with regretMore simulations and studies underway to address the Concerns raised by the PAC

blue: common withPVDISBlack: part in common with PVDISRed: This experiment only

SummaryThe study of chiral-odd quark distribution function and fragmentation function: an exciting, rapidly developing frontier, surprising flavor dependence observed in Collins and Sivers function, Worldwide effort Completed the 1st experiment at JLab

Future 11 GeV with Solenoid and polarized 3He target allows for a precision 3-d mapping of neutron Collins, Sivers, and pretzelocity asymmetries, and the extraction of transversity, Sivers and pretzlocity distribution functions.

Together with world proton results provides model independent determination of tensor charge of d quark. Provide benchmark test of Lattice QCD calculationsSupported by U.S. Department of Energy DE-FG02 03ER41231

Transversity from JLab Hall A Linear accelerator provides continuous polarized electron beamEbeam = 6 GeVPbeam = 85%3 experimental halls

*ABC

*This is where the experiment performed: Jefferson Lab, located in Newport News Virginia.The Jefferson Lab accelerator has two LINACs forming a circle and it can delivery electron beam up to 6 GeV with polarization around 85%.There are three experimental Halls at the end of the beam line and they are Hall A, B and C. The neutron transversity Im reporting was carried out in Hall A.

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