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Approved

CAA request : * Timelike Compton Scattering (e1-6 & e1-f) by R. Paremuzyan, S. Stepanyan et al. Committee : M. Guidal , C. Hyde & F. Sabatié 12 Yes’s , 0 No’s. Approved. Analysis reviews under course: * semi-inclusive p + , p 0 with long. Pol. Target (eg1)

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Approved

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  1. CAA request :*Timelike Compton Scattering (e1-6 & e1-f) by R. Paremuzyan, S. Stepanyan et al. Committee : M. Guidal, C. Hyde & F. Sabatié12 Yes’s, 0 No’s Approved

  2. Analysis reviews under course: *semi-inclusive p+,p0with long. Pol. Target (eg1) by H. Avakian et al. Committee : A. Biselli, S. Kuhn& K. Hafidi *semi-inclusive p0(e1-dvcs) by M. Aghasyan et al. Committee : K. Joo, F.-X. Girod & M. Osipenko *Inclusive proton double-spin asymmetries (eg1b) by R. Fersch et al. Committee : S. Niccolai, H. Avakian & R. DeVita *exclusive p+(e1-6) by K. Park et al. Committee : P. Stoler, S. Procureur & M. Ungaro

  3. Many thanks to F.-X. Girod for taking charge of the meeting on the other side of the water EVO+FX+Marco

  4. } e1-b (1999) K. Lukashin, Phys.Rev.C63:065205,2001 (f@4.2 GeV) } C. Hadjidakis et al., Phys.Lett.B605:256-264,2005 (r0@4.2 GeV) L. Morand et al., Eur.Phys.J.A24:445-458,2005 (w@5.75GeV) J. Santoro et al., Phys.Rev.C78:025210,2008 (f@5.75GeV) e1-6 (2001-2002) S. Morrow et al., Eur.Phys.J.A39:5-31,2009(r0@5.75GeV) Exclusive r0,w&f electroproduction on the proton @ CLAS M.Garçon, M. Guidal,C. Hadjidakis, K. Lukashin, L. Morand, S. Morrow, J. Santoro,E. Smith

  5. Longitudinal cross section sL(g*Lp  prL0)

  6. Interpretation “a la Regge” : Laget model g*p  pr0 g*p  pw Free parameters: *Hadronic coupling constants:gMNN *Mass scales of EM FFs:(1+Q2/L2)-2 g*p  pf

  7. sL (g*Lp  prL0) s,f2 Pomeron Regge/Laget

  8. VGG GPD model GK GPD model

  9. Laget sT+esL Issue with GPD approach if p0 exchange dominant : ~ p0->E VGG esL (H&E) Laget esL while ~ E subleading in handbag for VM production Cross sections(g*p  pw) LagetRegge model for g*p  pw

  10. Laget sT+esL W=2.9 GeV W=2.45 GeV W=2.1 GeV GK sL fL

  11. r w f

  12. Exclusive electroproduction of the r+on the proton at CLAS e(5.75 GeV) pe nr+e’ np+p0 AHMED FRADI Institut de Physique Nucléaire d’Orsay (France) CLAS Collaboration meeting Genoa, 27/02/2009

  13. Channel selection g g p+ e (p-) (p) e p e’ [n]r+e’ [n]p+p0 e’ [n] p+ g g EC An event in CLAS IC

  14. “Hadronic approach”: JML model r+ r0

  15. “Partonic approach”: GPDs (*) r+ r0 VGG GPD model GK GPD model

  16. Hint: 2 days ago: (Peter Kroll) mb/GeV2 ? dsL/dt (r+) ?

  17. dsL/dt (r0)

  18. Status of Semi-inclusive Pion Electroproduction Analysis for E1-F W. Gohn, K.Joo, M.Ungaro University of Connecticut H. Avakian Jefferson Lab CLAS12 European Workshop Feb. 27, 2009

  19. SIDIS Kinematics P Requires:

  20. Motivation for Measurement of Beam-Spin Asymmetry The beam-SSA provides important information about nucleon structure. A. Bacchetta, M. Diehl, K. Goeke, P. Mulders, & M. Schlegel, hep-ph/0611265v2, 2007 45

  21. Electron ID p npe*10 E/p should be constant in p for very fast electrons. Hence, all candidates outside of the red curves are cut. Electrons will leave many photoelectrons in the CC, so those candidates to the left of the blue line are cut to eliminate electric noise. 46

  22. Charged Pion Identification Here positive pions are shown as an example. The plots for negative pions are similar. p [GeV/c] M2 [GeV2] A cut is placed on mass-squared of 0.2, as determined by the time-of-flight system. M2 [GeV2] 47

  23. π0Identification Pions are selected from two-photon events in the EC. No internal calorimeter (IC) is used. Therefore we see a different kinematic range than do those experiments using an IC to detect neutral pions. Neutral pions are selected by putting a cut around the pion mass in the two-photon invariant mass spectrum Only photons with energy > 0.2 GeV are used. IM [GeV] 48

  24. Beam-Spin AsymmetriesFitting Procedure Error bars are statistical only. Ten bins in z and twelve in φ. Semi-inclusive range is expected to be for 0.4<z<0.7 for CLAS kinematics. Compared fits with and

  25. Sinφ Momentsz-dependence Isospin symmetry says π0 will give weighted average of charged pion results. Opposite deflections in current fragmentation region. Preliminary z-dependence of π0 could be related to g|. Charged π z-dependence has been shown to be related to Collins function.

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