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Measurement of Target Single Spin Asymmetry in Quasi-elastic 3 He (e, e’). (Updates on Ay experiment E05-015). Bo Zhao College of William and Mary For the Hall-A Quasi-elastic collaboration. 1. l'. l. H. P' q. P q. N'. N. k. k. k'. k'. P q. P q. P' q. P' q.
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Measurement of Target Single Spin Asymmetry in Quasi-elastic 3He (e, e’) (Updates on Ay experiment E05-015) Bo Zhao College of William and Mary For the Hall-A Quasi-elastic collaboration 1
l' l H P'q Pq N' N k k k' k' Pq Pq P'q P'q Two-photon Exchange progress 2
For Target Single Spin Asymmetry (SSA) In terms of GPD moments Y.C. Chen etc., PRL 93, 122301 (2004) A measurement of Ay has sensitivity to GPD model input 3
Expected result -1.35 Theoretical prediction 4
Ay Kinematics This Ay experiment (E05-015) was run from April 26th to May 12th The Kinematics of this Ayexperiment: 6
Electron Identification 7 Nphe (ADCs)
T1 scalar asymmetry between L and R Positive target spin Run number Negative target spin Run number 8
T3 scalar asymmetry between L and R Positive target spin Run number Negative target spin Run number 9
u3 scalar asymmetry between L and R Positive target spin Run number Negative target spin 10 Run number
Preliminary raw SSA Preliminary 11
Summary and future plan Preliminary raw SSA at Q2 = 0.98 is non-zero and consistent between L-arm data and R-arm data. An independent cross-check was being carried by E. Long. Target analysis by Y. Zhang was almost completed. Raw SSA at Q2 = 0.13 and Q2= 0.46 is almost finished and will be released soon after an independent cross-check. Systematic uncertainty study Raw SSA 3He SSA neutron SSA with dilution factor, target polarization and so on. 12
Preliminary 14