Nuclear Physics Working Group Meeting Nov 2, 2007 by 5gi202gp


									Nuclear Physics Working Group Meeting
             Nov 2, 2007

   14:00-14:10 Jerry Gilfoyle, Update on reviews.
   14:10-14:35 Kawtar Hafidi, Rho electroproduction off nuclei.
   14:35-15:00 Lorenzo Zana, EG2 Analysis Update.
          Current and Recent Reviews* - 1
Dan Protopopescu - Multipole Analysis of the Delta0(1232) in 3He
Committee:Kyungseon Joo (Chair), Mike Vineyard, Mike Wood

Hovhannes Baghdasaryan - 3He(e,e'pp)n Analysis
Committee:Mike Vineyard (Chair), Dan Protopopescu, Steffen Strauch

Avto Tkabladze - Photodisintegration of 4He to p+t
Committee:Dave Ireland (Chair), Yelena Prok, Stephen Bueltmann

Steve Manly and Bob Bradford - CAA: Measurements of Interest to the Neutrino Community
Committee: Kawtar Hafidi (Chair), Jeff Lachniet, Derek Bradford

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

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

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          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.

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

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                  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
            Analysis update for
      0 electroproduction off nuclei
                                      L. El Fassi, K. Hafidi, B. Mustapha

    Finite propagation distance lc
    (lifetime) of the (q,q-bar) virtual
    state.                                                      e + N → e’ + N + 0
         lc = 2/(M2 + Q2 )

•    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
                       Analysis Highlights
1. Background subtraction using
   two different Monte Carlo

2. Replace DE cut on exclusivity
   with one on z=E/ to reduce Q2

3. lc 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
6. Acceptance corrections …
                        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
4. Significant effect
   on transparency.
                   Summary and Conclusions
•   30% acceptance correction to the
    nuclear transparency ratio was

•   The acceptance correction for C and
    4 GeV Fe data is underway.

•   The systematic errors are almost

•   80% of the analysis note is
    completed (2 weeks to be

•   Lamiaa is writing her thesis and is
    expected to defend by February
         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 Ri = S j MijNj where Mij 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
5. Generated 25% of D2, 8% of carbon Monte Carlo events (100M each wanted).

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