Jin Huang PhD Candidate, MIT For Hall A Collaboration Meeting June 10, JLab

 World first measurement of the SSA and DSA in SIDIS Reaction  PAC29 approved with A rating  Major installation ◦ 3 He Target, BigBite Electron Package, LHRS RICH  Successful data taking from Oct 08 to Feb 09  Spokespersons Xiaodong Jiang (Rutgers/Los Alamos, Contact Person), Jian- ping Chen (JLab), Evaristo Cisbani (INFN-Rome), Haiyan Gao (Duke), Jen-Chieh Peng (UIUC)  7 Thesis Students ◦ K. Allada (Kentucky), C. Dutta (Kentucky), X. Qian (Duke) ◦ J. Huang (MIT), J. Katich (W&M), Y. Wang (UIUC), Y. Zhang (Lanzhou U) Hall A Collaboration Meeting Jin Huang 2

3 f 1T  = g 1T = h 1L  = h1 =h1 = h 1T = h 1T  = Transversity Boer-Mulder Pretzelosity Sivers Helicity Nucleon Spin Quark Spin f 1 = g 1 = : Probed by E Hall A Collaboration Meeting Jin Huang

Hall A Collaboration Meeting Jin Huang 4 Unpolarized Polarized Target Polarized Beam and Target Boer-Mulder Sivers Transversity Pretzelosity f 1 = f 1T  = g 1 = g 1T = h1 =h1 = h 1L  = h 1T  = h 1T = S L, S T : Target Polarization; e : Beam Polarization Worm-Gear

Hall A Collaboration Meeting Jin Huang 5  Polarized 3 He Target ◦ Spin Flip & 3D rotation ◦ 65% Polarization in experiment  Polarized Electron Beam ◦ ~80% Polarization ◦ Fast Flipping at 30Hz  BigBite at 30º as Electron Arm ◦ P e = 0.7 ~ 2.2 GeV/c ◦ MWDC/Shower/Scintillator  HRS L at 16º as Hadron Arm ◦ P h = 2.35 GeV/c ◦ VDC/S1&2/A1/Gas C/RICH/Lead Glass Beam Polarimetry (Møller + Compton) Luminosity Monitor

 Detector Calibration Done ◦ Reported in last collaboration meeting  Target analysis close to finalization  Extensive data quality checks  Two analysis teams cross check results ◦ Red Team: Maximum Likelihood Method ◦ Blue Team: Local Pair-Angular Bin-Fit Method ◦ Asymmetry results are consistent  Systematics in progress  Active theory supports Hall A Collaboration Meeting Jin Huang 6

  Polarimetry analyzed ◦ NMR/water calibration ◦ EPR  Target density close to finalized ◦ Density measurement ◦ Density w/ temperature correction  Temperature calibration coming soon  Final polarization table coming soon Hall A Collaboration Meeting Jin Huang 7 ~90% ~1.5% ~8%

 GEANT3 Simulation of BigBite ◦ COMGEANT based ◦ Rate study ◦ Confirmed electron arm contamination study Hall A Collaboration Meeting Jin Huang 8

 SIMC based simulation ◦ Coming soon  Construct BigBite  Update HRS/Target ◦ Simulating coinc event  pair contamination  diffractive ρ 0  cross section  bin centering  angular asymmetry extraction Hall A Collaboration Meeting Jin Huang 9

 Target spin sign ◦ Carefully checked/maintained/recorded  Beam helicity sign ◦ Important yet tricky  Could be easily flipped during installation/software ◦ No direct online check for 3 He experiments ◦ Off line checked with a consistent story  21 elastic/quasi-elastic data sets checked Also by B. Zhao, G. Jin  Spin precession calculation  Cross check sign with parity DAQ (with R. Michaels) ◦ Cross check welcome Hall A Collaboration Meeting Jin Huang 10

 Data Quality Check ◦ Run selection/beam trip cut/yield check/witness channel check  Cuts/contamination and systematic effect checked Hall A Collaboration Meeting Jin Huang 11

p T & ϕ h ± ϕ S Coverage Hall A Collaboration Meeting Jin Huang 12 Kinematics Coverage Q 2 >1GeV 2 W>2.3GeV z=0.4~0.6 W’>1.6GeV x bin 1 234

 It’s not simple! ◦ Spin flip/angular coverage/kinematics dependence  Two analysis team ◦ Independent method/code/compare results  Blue Team ◦ local pair-angular bin-fit method ◦ Low bias from yield drift ◦ ideal for pion spin asymmetry extraction  Red Team ◦ Maximum Likelihood method ◦ Tech note: ◦ Stable at low statistic/capable of high dimensional fit Hall A Collaboration Meeting Jin Huang 13

 Both asymmetry and modulation cross checked  Results are well consistent Hall A Collaboration Meeting Jin Huang 14

 3 He Collins SSAs are not large (as expected)  3 He Sivers SSAs follow the trend of Anselmino et al Hall A Collaboration Meeting Jin Huang 15

Hall A Collaboration Meeting Jin Huang 16

 Preliminary 3 He A LT ◦ Systematic uncertainty is still under work ◦ Projected neutron A LT stat. uncertainty : 6~10% Hall A Collaboration Meeting Jin Huang 17

 First measurement of angular modulated SSA and DSA in neutron ( 3 He) SIDIS  Data cover valence range  In progress: ◦ Simulation (coinc channel) ◦ Systematics ◦ Neutron asymmetry extraction ◦ Kaon A LT asymmetries  Submitting first paper in few months Hall A Collaboration Meeting Jin Huang 18

Systematics Table Hall A Collaboration Meeting Jin Huang 19

ItemSystematic Uncertainty N2 dilution 0.3~0.6% Relative Yield Drift PPM Relative MLE Non-local<100PPM Absolute Raw MLE Approximation125PPM Absolute Raw BigBite π− Cont.1~7% of Stat. Uncertainty BigBite Photon-induced electron Cont.~80%, 40%, 10%, 10% of Stat. Uncertainty Random Coincidence Correction10e-4 Absolute Raw HRS Kaon Cont.1.4e-4 Absolute Raw Bin Centering~10%, 6%, 10%, 20% of Stat. Uncertainty Target Density7PPM Absolute Raw Target Polarization5% Relative Beam Polarization3.8% Relative + 3.7% Rel. Left HRS Single Track<5e-5 Absolute Raw BigBite Tracking Quality~1e-4 for Pi-; <5e-5 for Pi+ Absolute Raw Livetime/Charge Asymmetry CorrectionMLE only: <10 PPM level Absolute Raw A_LL leak10~20% for Pi+ 5% for Pi- (Rel. to Stat. Uncer.) Hall A Collaboration Meeting Jin Huang 20