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E05-102 Analysis Update: Asymmetry Measurements in Quasi-Elastic Scattering

E05-102 Analysis Update: Asymmetry Measurements in Quasi-Elastic Scattering. Ge Jin University of Virginia for Jefferson Lab E05-102 Collaboration. Outline. asymmetry measurements Motivation Experimental Setup BigBite Calibration

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E05-102 Analysis Update: Asymmetry Measurements in Quasi-Elastic Scattering

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  1. E05-102 Analysis Update: Asymmetry Measurements in Quasi-ElasticScattering Ge Jin University of Virginia for Jefferson Lab E05-102 Collaboration

  2. Outline • asymmetry measurements • Motivation • Experimental Setup • BigBite Calibration • Inclusive asymmetry and neutron form factors extraction • PWIA Formulism • Inclusive Asymmetry Results • GEn Extraction Results

  3. 3He spin structure Spin-1/2 Particle, 3 spin-1/2 Nucleons (Proton and Neutron) Effective Neutron Target Angular Momentuml=0 l=0 l=2 ~90% ~1-2% ~8%

  4. Theoretical asymmetry from Faddeev Calculation

  5. BigBite optics and scintillator calibration Sieve

  6. Target calibration • Wall thickness • 3He density (absorbing spectra) • Polarization • Run-by-run EPR polarization • NMR ongoing • Dilution factor

  7. Inclusive GEn Extraction(Q2=0.95 GeV2) 3He Inclusive Responses at Q.E. peak Transverse: Longitudinal: where H’s are described by momentum distribution within PWIA Proton: HpT’ Neutron: Hn Proton: HpTL’ A. Kievsky, E. Pace, G. Salme’ and M. Viviani, PRC 56 (1997) p.64

  8. Quasi-elastic asymmetry where v’s are kinematics factors, θ and φ describe the direction between q vector and target polarization T. D. Donnelly and A. S. Raskin, Ann. Phys 169, 247 (1986)

  9. Ratio of Inclusive Asymmetry ATL’/AT’ Longitudinal: Transverse: Asymmetry ratio: Where v’s are kinematics factors • By measuring ATL’/AT’ and using GEp , GMn , GMn as known parameters can one extract GEn

  10. Asymmetry Results • Kinematics: • 3 pass beam, HRS-R 170, Q2=0.95 GeV2 • Analysis: • Asymmetry in 0.9<x<1.1 • Yawei Zhang’s target and dilution factor analysis • Karl Slifer’s radiative correction code radcor.f • Results: • ATL’=-0.55±0.09(stat)±0.04(syst)% • AT’ =3.12±0.10(stat)±0.21(syst)% • Error: • Stat error dominates ATL’ • Syst error contributed by beam and target polarization, and dilution factor

  11. Asymmetry Ratio and GEn Extraction • Ratio: • ATL’/AT’ =-0.18±0.032(stat)±0.004(syst) • Error • Dominated by stat in ATL’ case • Small sensitivity systematically • GEn Extraction • GEn/GD=0.26±0.047(stat)±0.005(syst)±(theory) • or GEn=0.048±0.0086(stat)±0.0009(syst)±(theory) • Using J. Kelly’s parameterization for GEp ,GMn , GMn

  12. World GEn Data J. J. Kelly, PRC 068202, 2004 S. Riordan, thesis, 2008

  13. Comments and Outlook • Further theoretical support (at and around Q.E peak) • Advantages: • Single arm (HRS) detector calibration • Higher Q2 with stronger GEn contribution in ATL’ • Big save of beam time: 18% accuracy in 2-day running • Double-ratio method insensitive to systematic error

  14. Graduate Students G. Jin, University of Virginia E. Long, Kent State University M. Mihovilovič, Jožef Stefan Institute Y. Zhang, Lanzhou University Run Coordinators A. Camsonne, Jefferson Lab P. Monaghan, Hampton University S. Riordan, University of Virginia B. Sawatzky, Temple University R. Subedi, University of Virginia V. Sulkosky, MIT Y. Qiang, Duke University B. Zhao, College of William and Mary Thanks to the Hall A Quasi-Elastic Family Experiments Spokespersons T. Averett, College of William and Mary (E05-015, E08-05) J. P. Chen, Jefferson Lab (E05-015) S. Gilad, MIT (E05-102) D. Higinbotham, Jefferson Lab (E05-102, E08-005) X. Jiang, Rutgers University (E05-015) W. Korsch, University of Kentucky (E05-102) B. E. Norum, University of Virginia (E05-102) S. Sirca, University of Ljubljana (E05-102) V. Sulkosky, MIT (E08-005) E05-015, E08-005, and E05-102 Collaboration K. Allada B. Anderson J. R. M. Annand W. Boeglin P. Bradshaw M. Canan C. Chen R. De Leo X. Deng A. Deur C. Dutta L. El Fassi D. Flay F. Garibaldi H. Gao R. Gilman F. Salvatore M. Shabestari A. Shahinyan B. Shoenrock J. St. John A. Tobias W. Tireman G. M. Urciuoli D. Wang K. Wang J. Watson B. Wojtsekhowski Z. Ye X. Zhan X. Zheng L. Zhu S. Golge O. Hansen T. Holmstrom J. Huang H. Ibrahim E. Jensen M. Jones H. Kang J. Katich C. W. Kees P. King J. LeRose R. Lindgren H. Lu W. Luo P. Markowitz M. Meziane R. Michaels B. Moffit N. Muangma H. P. Khanal K. Pan D. Parno E. Piasetzky M. Posik A. J. R. Puckett X. Qian X. Qui A. Saha

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