1. Nuclear Physics Working Group Meeting Nov 2, 2007 Agenda 14:00-14:10Jerry Gilfoyle, Update on reviews. 14:10-14:35 Kawtar Hafidi, Rho electroproduction off nuclei. 14:35-15:00Lorenzo Zana, EG2 Analysis Update.

2. Current and Recent Reviews* - 1 Dan Protopopescu - Multipole Analysis of the Delta0(1232) in 3He Committee:Kyungseon Joo (Chair), Mike Vineyard, Mike Wood ongoing Hovhannes Baghdasaryan - 3He(e,e'pp)n Analysis Committee:Mike Vineyard (Chair), Dan Protopopescu, Steffen Strauch ongoing Avto Tkabladze - Photodisintegration of 4He to p+t Committee:Dave Ireland (Chair), Yelena Prok, Stephen Bueltmann ongoing Steve Manly and Bob Bradford - CAA: Measurements of Interest to the Neutrino Community Committee: Kawtar Hafidi (Chair), Jeff Lachniet, Derek Bradford ongoing Alex Vlasov – CAA: Source size measurements in the eHe -> e'p  X reaction. Committee: Larry Weinstein (chair), Pavel Degtyarenko approved Mikhail Osipenko, G. Ricco, S.Simula, M.Battaglieri, R. DeVita, M. Ripani, M. Taiuti, M. Anghinolfi – CAN: Moments of the nucleon structure function F2 with CLAS: Part III – nuclear target. Committee: Mike Dugger (chair), Tony Forest, Rakhsha Nasseripour ongoing * If you want to modify this list send email to gilfoyle@jlab.org

3. Current and Recent Reviews* - 2 Werner Boeglin, Brian Raue, Misak Sargsian, Stepan Stepanyan – CAA: Proposal for a CLAS Approved Analysis of e6 Data to Study the Re-Scattering of the S11 Resonance in the Deuteron, Committee: Barry Ritchie (chair), Nerses Gevorgyan. ongoing R. Avakian, L. N. Ananikyan, N. Ya. Ivanov, B. L. Berman, Y. Y. Ilieva, P. Nadel-Turonski, M. Mirazita, P. Rossi, K. Livingston, H. Avakian and V. D. Burkert - CAA: Determination of the Azimuthal Asymmetry in Deuteron Disintegration by Linearly Polarized Photons at Egamma = 1.1 - 2.3 GeV Committee: TBA * If you want to modify this list send email to gilfoyle@jlab.org

4. Proposal Reviews for PAC33 Medium Modification of , ,  – update of g7b –Mike Wood –Committee: TBA Direct Measurement of lifetime of heavy nuclei using fission fragment detection technique and CLAS with a real photon beam. –L. Tang, A. Margaryan, B. Raue, and B. Hu –Committee: TBA

5. Analysis update for  0 electroproduction off nuclei L. El Fassi, K. Hafidi, B. Mustapha e + N → e’ + N +  0 Finite propagation distance l c (lifetime) of the (q,q-bar) virtual state. l c = 2 /(M 2 + Q 2 ) W  2 GeV  avoid resonance region -t  0.45 GeV2  select diffractive process |ΔE| ≤ 0.1GeV  select exclusive channel ΔE = - E  + t/2Mp is the missing energy from  +  - pair due to the creation of any additional final state particles

6. Analysis Highlights 1.Background subtraction using two different Monte Carlo calculations.. 2.Replace  E cut on exclusivity with one on z=E  / to reduce Q 2 dependence. 3.l c dependence of transparency is flat so it can be summed over to enhance statistics. 4.Radiative corrections are small in the transparency ratio. 5.Rigorous correction for pion absorption correction performed and validated by Sargsian and Miller. 6.Acceptance corrections …

7. Acceptance Corrections 1.MC Model EA-VM (Brahim Mustapha). Compares well with data. 2.Binning: - Q2 ( [0.8, 2 GeV2 ], 4 bins - t ( [0.1, 0.4 GeV2], 2 bins - W ( [2, 3.2 GeV2], 3 bins - M  integrate over - p  ( [1.8, 4.5 GeV ], 4 bins -  decay ( [0, 180 deg], 6 bins -  decay integrate over -  (hadronic, leptonic) integrate over 3. For each target: 200M generated events  1.5M accepted  220K in desired kinematics. 4. Significant effect on transparency.

8. Summary and Conclusions 30% acceptance correction to the nuclear transparency ratio was found. The acceptance correction for C and 4 GeV Fe data is underway. The systematic errors are almost completed. 80% of the analysis note is completed (2 weeks to be completed) Lamiaa is writing her thesis and is expected to defend by February

9. A Measurement of the Nuclear Transparency for  0 : An outline of the analysis of the D2+Carbon data Lorenzo Zana, L. Elfassi, M. Holtrop, K. Hafidi, B. Mustapha, eg2 collaborators, 1.Parallel analysis to ANL group in previous talk. 2.Radiative Corrections will be studied using the EV-AM Monte Carlo from B. Mustapha in GSIM with radiative effects on and off. 3.Acceptance corrections. 1.Fermi motion parameterized in Monte Carlo. 2.Binning. 4.Determination of the bin migration matrix. 1.The matrix is R i =  j M ij N j where M ij represents the probability that an event in bin j migrates to bin i. 2.Minimize the dimension of Mij by using only nearest neighbor bins. 3.Generate separate diagonal dilatation matrix (efficiencies) and deformation matrix (bin migration effects) to make it easier to extract the acceptance correction. 5.Generated 25% of D2, 8% of carbon Monte Carlo events (100M each wanted).