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E06007, March 3 -> March 26, 2007

E06007, March 3 -> March 26, 2007. 208 Pb(e,e’p) 207 Tl, 209 Bi(e,e’p) 208 Pb. x=1, q = 1 GeV/c, w = 0.433 GeV, Q 2 = 0.81 to 1.97 (GeV/c) 2. Impulse Approximation limitations to the (e,e',p) reaction on 208 Pb, identifying correlations and relativistic effects in the nuclear medium.

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E06007, March 3 -> March 26, 2007

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  1. E06007, March 3 -> March 26, 2007 208Pb(e,e’p)207Tl, 209Bi(e,e’p)208Pb x=1, q = 1 GeV/c, w = 0.433 GeV, Q2 = 0.81 to 1.97 (GeV/c)2 Impulse Approximation limitations to the (e,e',p) reaction on 208Pb, identifying correlations and relativistic effects in the nuclear medium Students: Juan Carlos Cornejo (CSULA) Joaquin Lopez (U. Madrid)

  2. 1) Objectives of the Experiment 2) Run time experience 3) Activity to date 4) Anticipated direction for analysis

  3. 1) Objectives (I) Long Range Correlations search a) Measure spectroscopic factors for states near the Fermi level. Spectroscopic factors depend on SRC and LRC. b) Measure cross sections for these low lying states to 500 MeV/c in pmiss. Excess strength here is theoretically identified as due to LRC. c) Search for Q2 dependence of spectroscopic factors.

  4. 1) Objectives (II) Identify dynamical relativistic effects in nuclear structure. Measure cross section asymmetry ATL around the three momentum transfer. Relativistic mean field theory predicts an ATL dependence on pmiss< 300 MeV/c due to dynamical enhancement of the lower component of the nucleon wave function. Calculations which do not include the enhancement of the lower component predict a substantially different ATL behavior.

  5. 2) Run time experience OPTICS STUDIES E=1.343 GeV, optics studies for RHRS, LHRS E = 2.649 GeV, optics studies for LHRS Aim to get dY<100 uM, dEbeam/Ebeam < 2.5 e-5 Internal and external sieve slits in/out delta scans raster on/off

  6. Online data base

  7. 12C(e,e’p)11B, small acceptance GEANT simulation using nominal spectrometer resolutions plus data with online optics data base. sm 815 keV

  8. 12C(e,e’p)11B, full acceptance cut GEANT simulation fitted to spectrometer resolutions plus data with online optics data base. 1 MeV Emiss

  9. 12C(e,e’p)11B, raster off, full acceptance GEANT simulation fitted to spectrometer resolutions plus data with online optics data base.

  10. Progress in data base change

  11. 2) Run time experience Diamond sandwich targets, 4mmx4mm raster Targets: C/Pb/C, C/Pb/C, C/Bi/C, C(non diamond) Initially accelerator could not provide 100 uA with desired beam characteristics. Ran for 2 days at 55 uA on Pb tgt#4. Beam current increased to 85 uA and target Pb#4 failed. Bi target run at 80 uA for about 45 minutes with no sign of failure. For next two weeks we ran at 45 uA on Pb tgt#3 and Bi with no sign of degradation.

  12. Fracture in the diamond foil

  13. Pmiss=0 MeV/c C Pb

  14. GEANT simulation, C with Pb kinematics, pmiss = 0 MeV/c 11B gs and no 207Tl continuum C Pb dp/p = +- 1.0e-4, dh = +- 0.3mr, dv = +- 1.0mr

  15. Pb target, pmiss = 200 MeV/c

  16. Pb tgt, 200 MeV/c simulation

  17. Pb, pmiss = 300 MeV/c

  18. Pb, simulation, pmiss = 300 MeV/c

  19. Pb, pmiss = -300 MeV/c

  20. Simulation, Pb, pmiss = -300MeV/c

  21. 3) Activity to date Apply simulation to C data. Analyze optics runs 4) Anticipated direction for analysis Replay Pb and Bi data as C to get best carbon peaks. Find values of spectrometer parameters to match carbon peaks. Use spectrometer parameters to generate geant shapes for the unfolding of the Tl states.

  22. Q2 = 1.40 GeV2, pmiss = 0 MeV/c

  23. Q2 = 1.97 GeV2, pmiss = 0 MeV/c

  24. pmiss=400 MeV/c, charge = 1.72 Coulombs, Pb

  25. Simulation, pmiss = 400 MeV/c, charge = 7.2 Coulomb, Pb

  26. High pmiss data • Pmiss Coul obtained Coul proposed • 400 1.72 7.2 • -400 1.15 10.8 • 1.37 8.6 • -500 0.89 8.6

  27. 3 MeV 208Pb(e,e’p)207Tl Emiss with Bi geant superposed Using the online data base

  28. 0 100 200 MeV/c 208Pb(e,e’p)207Tl

  29. 209Bi(e,e’p)208Pb, pmiss = 200 MeV/c, online optics data base 3 MeV

  30. 209Bi(e,e’p)208Pb, pmiss = 200 MeV/c, Guido’s recent optics update 2.2 MeV

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