Nuclear Physics Working Group Meeting May 30, 2008 A110 Agenda 13:30-13:40Jerry Gilfoyle, Update on reviews. 13:40-14:05 Kawtar Hafidi, EG2 analysis update - I 14:05-14:30Larry Weinstein, Correlated pp to np pair ratios in 3 He(e,e'pp)n 14:30-14:55 Mikhail Osipenko, Update on inclusive scattering from E2a 14:55-15:15 Break 15:15-15:40 Lorenzo Zana, EG2 analysis update – II 15:40-15:55 Steve Manly, Update on EG2 charged pion analysis 15:55-16:20 Aji Daniel, Preliminary results on the nuclear dependence of the multiplicity ratios of neutral kaons 16:20-16:45 Rakhsha Nasseripour, Photodisintegration of 4 He to p and t

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 Rakhsha Nasseripour - Photodisintegration of 4He to p+t Committee:Dave Ireland (Chair), Yelena Prok, Stephen Bueltmann ongoing Alex Vlasov – CAN: Source size measurements in the eHe -> e'p  X reaction. Committee: Larry Weinstein (chair), Pavel Degtyarenko, Yordanka Ilieva ongoing 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 to

Current and Recent Reviews* - 2 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 = GeV Committee: Haiyan Gao, Eugene Pasyuk approved approved by Collaboration May 29, * If you want to modify this list send to

Proposal Reviews for PAC33 Medium Modification of , ,  – update of g7b –Mike Wood –Committee: Gabriel Nicelescu and Enzo DeSanctis –approved –conditionally approved by PAC33 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: R.Schumacher, K.Hicks, B.Quinn –declined

L. Weinstein, Gordon Correlations in 3He(e,e’pp)n Larry Weinstein Contradiction??? Subedi et al, Science (2008) E beam pn to pp ratio Hall A / BNL 2 / ??18 2 GeV GeV Hall A BNL Hall ABNL np/2N pp/2N

L. Weinstein, Gordon pp to pn resolution: pp/pn ratio increases with pair total momentum P tot Theory: Wiringa, Schiavilla, Pieper and Carlson Hall A: small P tot  less pp Hall B: large P tot  more pp Small P tot  pp pair in s-wave (no tensor)  wave fn minimum at p rel =400 MeV/c 300 < P relative < 500 MeV/c Preliminary Tensor Correlations! Hall A / BNL

L. Weinstein, Gordon He(e,e’pp)n Summary Analysis - follow the peaks p n < 250 MeV/c:  pp ≈ 90 o  rescattering dominated p N > 250 MeV/c Peaks at corners of Dalitz plots (T 1, T 2 < 0.2 ) Cut p leading (perp) < 300 MeV/c: reduce leading N FSI Results: NN pair is back-to-back Small p total along q Isotropic Momentum distributions similar for 2.2 and 4.7 GeV Moderate agreement with theory pp to pn pair ratio increases with P total 3N correlations??? We have measured distorted correlated pairs!

Extraction of the Nuclear Structure Function F2 From E2a Data Mikhail Osipenko Structure functions agree with world data and at different beam energies. CLAS data dramatically increase kinematical coverage. Carbon target

Extraction of the Nuclear Structure Function F2 From E2a Data

A Measurement of the Nuclear Transparency for r 0 ; An Analysis of the Carbon+D2 Data Lorenzo Zana

Analysis of Pion Production in eA – for “neutrino engineering” Melanie Day, Hyupwoo Lee, Steve Manly - Univ. of Rochester  Idea is to measure basic quantities (like differential pion cross sections) on different A to facilitate tuning of nuclear effects in neutrino experiment simulations - quite important for current/future high precision neutrino expts.  Have talked about it for a few years, so far only able to do “summer student” research on the problem.  Now have two neutrino grad students starting to do the dirty work necessary to actually make a measurement/paper.  Talking to experts on acceptance, radcorr, normalization, etc., hoping to avoid ‘reinventing the wheel’.  Making data plots with eg2 data (D 2 and C), learning subtleties with GSIM, looking for pion generator/model, starting to look at normalization.

Nuclear Dependence of K 0 Hadronization Aji Daniel Quark Propagation and Hadron Formation – Measure the space- time properties of hadron formation. Focus on the formation time t h f ; the time for the pre-hadron to evolve into a fully-dressed hadron (C, Fe, Pb targets). Hermes results EG2 π + preliminary

Nuclear Dependence of K 0 Hadronization Use the π + π - decay channel to reconstruct the K 0. Additional cuts on the pion vertex time and the trigger time To do. ?? Significant Target dependence

Rakhsha Nasseripour,Barry Berman, Yordanka Ilieva 1/28/201615Nuclear Physics WG Meeting PHOTODISINTEGRATION of 4 He to p + t Reaction Mechanisms and Theoretical Calculations One-body : proton or triton exchange Two-body : two nucleon meson exchange and nucleon- nucleon rescattering Three-body : meson double scattering

Background-Free Event Selection Kinematics of real pt events require: E(x) = 0 GeV P(x) = 0 GeV/c M(X) 2 = 0 (GeV/c 2 ) 2  pt = 180 deg Acceptance Corrections Cross Sections (Energy Dependence) One-body Two-body Three-body Laget Model

We have extracted the cross sections for the photodisintegration of 4He to pt for photon energies above 0.4 GeV and proton scattering angles between 40 and 140 degrees. We have extracted the cross sections for the photodisintegration of 4He to pt for photon energies above 0.4 GeV and proton scattering angles between 40 and 140 degrees. Comparison with Laget model confirms the importance of the contribution of the three-body mechanisms at lower photon energies and large angles. Comparison with Laget model confirms the importance of the contribution of the three-body mechanisms at lower photon energies and large angles. Analysis of systematic uncertainties is underway. Analysis of systematic uncertainties is underway. Our analysis note is nearly completed. Our analysis note is nearly completed. We request for an Analysis Review Committee. We request for an Analysis Review Committee. 1/28/2016Nuclear Physics WG Meeting17 Summary