Nuclear Physics Working Group MeetingMay 30, 2008 A110

Agenda

13:30-13:40 Jerry Gilfoyle, Update on reviews.13:40-14:05 Kawtar Hafidi, EG2 analysis update - I14:05-14:30 Larry Weinstein, Correlated pp to np pair ratios in 3He(e,e'pp)n14:30-14:55 Mikhail Osipenko, Update on inclusive scattering from E2a14:55-15:15 Break15:15-15:40 Lorenzo Zana, EG2 analysis update – II15:40-15:55 Steve Manly, Update on EG2 charged pion analysis15:55-16:20 Aji Daniel, Preliminary results on the nuclear dependence of the multiplicity ratios of neutral kaons16:20-16:45 Rakhsha Nasseripour, Photodisintegration of 4He 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 Woodongoing

Hovhannes Baghdasaryan - 3He(e,e'pp)n AnalysisCommittee:Mike Vineyard (Chair), Dan Protopopescu, Steffen Strauchongoing

Rakhsha Nasseripour - Photodisintegration of 4He to p+tCommittee:Dave Ireland (Chair), Yelena Prok, Stephen Bueltmannongoing

Alex Vlasov – CAN: Source size measurements in the eHe -> e'p X reaction.Committee: Larry Weinstein (chair), Pavel Degtyarenko, Yordanka Ilievaongoing

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 Nasseripourongoing

* If you want to modify this list send email to gilfoyle@jlab.org

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 = 1.1 - 2.3 GeVCommittee: Haiyan Gao, Eugene Pasyukapprovedapproved by Collaboration May 29, 2008.

* If you want to modify this list send email to gilfoyle@jlab.org

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 2004 5

Correlations in 3He(e,e’pp)nLarry Weinstein

Contradiction???

Subedi et al, Science (2008)

Ebeam <Q2> pn to pp ratio

Hall A / BNL

2 / ?? 18

2 GeV 0.8 3.14.7 GeV 1.5 4.5

Hall ABNL

Hall ABNL

np/2N

pp/2N

L. Weinstein, Gordon 2004 6

pp to pn resolution:pp/pn ratio increases with pair total

momentum Ptot

Theory: Wiringa, Schiavilla, Pieper and Carlson

Hall A: small Ptot less ppHall B: large Ptot more pp

Small Ptot pp pair in s-wave (no tensor) wave fn minimum at prel=400 MeV/c

300 < Prelative < 500 MeV/c

Prelim

inary

TensorCorrelations!

Hall A / BNL

L. Weinstein, Gordon 2004 7

3He(e,e’pp)n Summary•Analysis - follow the peaks

• pn < 250 MeV/c: pp ≈ 90o rescattering dominated• pN > 250 MeV/c

• Peaks at corners of Dalitz plots (T1, T2 < 0.2)• Cut pleading(perp) < 300 MeV/c: reduce leading N FSI

•Results:• NN pair is back-to-back• Small ptotal along q• Isotropic• Momentum distributions similar for 2.2 and 4.7 GeV• Moderate agreement with theory• pp to pn pair ratio increases with Ptotal

• 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 r0; 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 (D2 and C), learning subtleties with GSIM, looking for pion generator/model, starting to look at normalization.

Nuclear Dependence of K0 Hadronization

Aji DanielQuark Propagation and Hadron Formation – Measure the space-time properties of hadron formation.

Focus on the formation time thf; the time for

the pre-hadron to evolve into a fully-dressed hadron (C, Fe, Pb targets).

Hermes resultsEG2 π+ preliminary

Nuclear Dependence of K0 Hadronization

Use the π+π- decay channel to reconstruct the K0.

Additional cuts on the pion vertex time and the trigger time

To do.

??

Significant Target dependence

Rakhsha Nasseripour,Barry Berman, Yordanka Rakhsha Nasseripour,Barry Berman, Yordanka IlievaIlieva

05/03/23 15Nuclear Physics WG Meeting

PHOTODISINTEGRATION of 4He 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 GeVP(x) = 0 GeV/cM(X)2 = 0

(GeV/c2)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 We have extracted the cross sections for the photodisintegration of 4He to pt for photon energies photodisintegration of 4He to pt for photon energies above 0.4 GeV and proton scattering angles between above 0.4 GeV and proton scattering angles between 40 and 140 degrees. 40 and 140 degrees.

Comparison with Laget model confirms the importance Comparison with Laget model confirms the importance of the contribution of the three-body mechanisms at of the contribution of the three-body mechanisms at lowerlower photon energies and large angles.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.

05/03/23 Nuclear Physics WG Meeting 17

Summary