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STATUS OF THE E06-007 EXPERIMENT

STATUS OF THE E06-007 EXPERIMENT Impulse Approximation limitations to the (e,e’p) reaction on 208 Pb, 209 Bi and 12 C. Students : Juan Carlos Cornejo, Joaquin Lopez Herraiz Jlab staff: Alexandre Camsonne Spokepersons: K. Aniol, A. Saha, J. M. Udias, G. Urciuoli

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STATUS OF THE E06-007 EXPERIMENT

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  1. HALL A COLLABORATION MEETING 16 DECEMBER 2009 STATUS OF THE E06-007 EXPERIMENT Impulse Approximation limitations to the (e,e’p) reaction on 208Pb, 209Bi and 12C Students: Juan Carlos Cornejo, Joaquin Lopez Herraiz Jlab staff:Alexandre Camsonne Spokepersons: K. Aniol, A. Saha, J. M. Udias, G. Urciuoli and the Jefferson Lab Hall A Collaboration

  2. HALL A COLLABORATION MEETING 16 DECEMBER 2009 INDEX • MOTIVATION and THEORY • DATA ANALYSIS - Checks • - Some results on 12C(e,e’p) and 208Pb(e,e’p) from J.L.Herraiz, June 2009 Hall A meeting • NEW RESULTS FROM MEASURED DATA- 209Bi(e,e’p) • SUMMARY

  3. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Nuclear States of interest in E06-007 209Bi 208Pb 207Tl MeV MeV MeV 0.0 3s1/2 0.351 2d3/2 1.348 1h11/2 1.683 2d5/2 3.470 1g7/2 0.0 0+ ~4.1 1p1h ~5.4 1p1h 0.0 1h9/2, proton

  4. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Long Range Correlations ? Ambiguous Interpretation xB = 0.18 E. Quint, thesis, 1988, NIKHEF I. Bobeldijk et al.,PRL 73 (2684)1994 J. M. Udías et al. PRC 48(2731) 1994 J.M. Udías et al. PRC 51(3246) 1996 If long range correlations are the reason for the small spectroscopic factors, then they should produce a large effect at high missing momentum. An experiment was performed at NIKHEF-K to measure the large momentum region, but the kinematics was far from XB=1. Additional strength was indeed found, but this can be explained either via long-range correlations or by relativistic effects in the mean field model.

  5. HALL A COLLABORATION MEETING 16 DECEMBER 2009 With correlations Without correlations Choice of Kinematics At XB = 1 both a relativistic and nonrelativistic theoretical treatment agree and excess strength at high pmiss is predicted by both approaches if LRC exist. 208Pb(e,e’p) Simulated theoretical calculations Previous experiment at NIKHEF (Bobeldijk, PRL 1994) found an excess of strength at high pmiss in 208Pb(e,e’p). This was explained by two approaches: (1) Quasiparticle orbits plus non-relativistic DWIA. (2) Relativistic DWIA using independent particle orbit solutions to Dirac equation. Measuring the high pmiss region at the quasielastic peak with good statistics will reveal if long-range correlations are needed to describe the data.

  6. HALL A COLLABORATION MEETING 16 DECEMBER 2009 209Bi(e,e'p)208Pb is also an interesting study A previous study of electron and photon induced knockout from 209Bi D. Brandford et al.,PRC 63 014310 (2000) (e,e'p)-parallel kinematics, Ee=293,412 MeV, Tp = 100 MeV 110<pmiss<290 MeV/c 208Pb(g.s.) 208Pb(hole states) (e,e'p) E06007- primary goal here is to isolate the 208Pb gs by the knockout of the 1h9/2 proton in 209Bi. The first excited state of 208Pb is at 2.6 MeV(3-) which is weakly excited in (e,e'p) gamma,p 2nd goal is to excite the 1p1h Proton configurations in 208Pb

  7. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Proton orbitals which are important for the low lying states. In 209Bi, 208Pb and 207Tl. From earlier proton removal experiments and the data of Brandford the strong excitations at 4.1 and 5.4 MeV have proton particle hole configurations given by [1h9/2,(3s1/2)-1] [1h9/2,(2d3/2)-1] [1h9/2,(1h11/2)-1] 209Bi – model structure [1h9/2,(2d5/2)-1] There are many states in this energy region which also have large neutron particle-hole configurations(PRC 74 034303 (2006)) but the (e,e'p) reaction is selecting the proton hole configuration.

  8. HALL A COLLABORATION MEETING 16 DECEMBER 2009 1. EXPERIMENT E06-007 • We measured 208Pb(e,e’p), 209Bi(e,e’p) and 12C(e,e’p) cross sections at true quasielastic kinem. (xB=1, q=1GeV/c, ω=0.433GeV/c) at both sides of q. OBJECTIVES • Determine momentum distributions: 0< pmiss< 500MeV/c • Determine ATL by measuring cross sections on either side of q • Determine the spectroscopic factors dependence with Q2 (0.81, 1.40, 1.97 GeV2)

  9. HALL A COLLABORATION MEETING 16 DECEMBER 2009 1. EXPERIMENT E06-007 • Data acquisition: • RUN 1 – (March, 3-26, 2007) • RUN 2 – (January 2008) Additional measurements in Lead in the high pmiss region. With thin and thick lead target. • Targets: • Diamond/Lead/Diamond • Diamond/Bismuth/Diamond sandwich cryogenic target 0.2mm Pb + 0.3mm Diamond 0.2mm Bi + 0.3mm Diamond (needed for high beam current). Requirements: - Good Energy Resolution - Raster Correction - Normalization Factors - Use 12C as a reference

  10. HALL A COLLABORATION MEETING 16 DECEMBER 2009 3. DATA ANALYSIS: Emiss Resolution Pmiss = 0-100MeV/c

  11. HALL A COLLABORATION MEETING 16 DECEMBER 2009 3. DATA ANALYSIS: Emiss Resolution Two peaks can be separated in this 208Pb(e,e'p)207Tl Emiss spectrum (Pmiss=0). Both of them are composed of two peaks. Boron states from 12C(e,e'p)11B Ex=[0-2.5] Ex=[2.5-7.5] Thallium Valence states

  12. HALL A COLLABORATION MEETING 16 DECEMBER 2009 GRAPHITE DIAMOND 3. DATA ANALYSIS: Luminosity and Raster 1 ) In order to get Absolute Cross Sections we should know the Luminosity very precisely. 2 ) Nevertheless C+Bi+C target had a problem and Bismuth only covered one-half of the target. Furthermore, the raster pattern was not uniform at the edges. 3 ) A simple approach (ratio between areas) may not be entirely accurate. To estimate luminosities, we compared the measured cross-section in the region of the target with only diamond foils against the events measured with the graphite target, both with Raster on and off. Y X

  13. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 209Bi(e,e’p)208Pb Emiss spectrum,pmiss = 200 MeV/c boron leadhole States Ex=[0-3.0] Lead g.s. From Bismuth 1h9/2 state

  14. HALL A COLLABORATION MEETING 16 DECEMBER 2009 209Bi(e,e’p)208Pb ground state CROSS-SECTION Integrated over the detector acceptances geant simulation, Coulombs scaled by area of Bismuth to total area in the raster pattern. PRELIMINARY Cross-Section Emiss

  15. 209Bi(e,e’p)208Pb ground state PRELIMINARY Independent analysis using MCEEP simulation for kinematic runs at pmiss = 100, 200 and 300 MeV/c. Luminosities estimated from the comparison to carbon(graphite) data.

  16. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Comparison of hole states in 208Pb and valence states in 207Tl Pmiss = 200 MeV/c 11B states The two spectra have been normalized by the luminosities . The Raster cut has been applied so that the carbon/metal ratios are the same in the two spectra. 208Pb(e,e'p)207Tl 208Pb, g.s. 209Bi(e,e'p)208Pb, hole states

  17. PRELIMINARY The shape of the pmiss distribution is fitted well assuming the same proton orbitals are important for the 1p1h states in 208Pb as the proton orbitals used in the 207Tl states Integrated cross section over the particle hole states in 208Pb Luminosities were estimated by comparing the carbon events from the diamond-foils-only region of the target to the same kinematics with the graphite target.

  18. HALL A COLLABORATION MEETING 16 DECEMBER 2009 PRELIMINARY SIMULATION DATA 4. RESULTS: 208Pb(e,e’p) RED. CROSS-SECTION (Emiss region –Ex=0..7.5MeV-) 207Tl states

  19. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Results from D. Brandford etal., PRC 63 014310 (2000)

  20. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Summary Analysis is ongoing for the 209Bi data – extract cross sections on both sides of the three momentum transfer. Theses writing is being finished Papers on the results are being written: - long range correlation implications for 208Pb(e,e'p)207Tl - Q2 dependence on the spectroscopic factors for 208Pb(e,e'p)207Tl and 12C(e,e'p)11B - ATL dependence on pmiss - 209Bi(e,e'p)208Pb cross sections

  21. HALL A COLLABORATION MEETING 16 DECEMBER 2009 BACKUP SLIDES

  22. boron leadhole States DATA SIMULATION pmiss = 200MeV/c Bismuth 1h9/2 state

  23. KIN 2 KIN 4

  24. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Results from D. Brandford etal., PRC 63 014310 (2000)

  25. HALL A COLLABORATION MEETING 16 DECEMBER 2009

  26. HALL A COLLABORATION MEETING 16 DECEMBER 2009

  27. HALL A COLLABORATION MEETING 16 DECEMBER 2009 HOW MUCH HYDROGEN IS THERE? · LEAD TARGET: NucleiH ~0.12% NucleiPb (.t)H~5.8E-6 (.t)Pb = 1.13E-6 g/cm2 tH ~ 1E-8m · GRAPHITE TARGET (RUN 1): NucleiH ~0.016% NucleiC (.t)H~2.2E-5 (.t)C = 1.9E-6g/cm2 tH ~ 2E-8m

  28. HALL A COLLABORATION MEETING 16 DECEMBER 2009

  29. HALL A COLLABORATION MEETING 16 DECEMBER 2009 2. THEORY AND SIMULATIONS

  30. HALL A COLLABORATION MEETING 16 DECEMBER 2009 Good Coincidence Time 3. DATA ANALYSIS – Calibration • - The first part of the data analysis consisted in: • Improving the Optics Database to get 1MeV resolution. • Improving the Coincidence Time (resolution 2.5ns). • Establishing the Raster Correction (we used a large raster) • Normalization factors (Dead-time,Multitracks correction) - This part of the analysis is almost finished and we obtain reasonable good results: RASTER ON RASTER OFF

  31. HALL A COLLABORATION MEETING 16 DECEMBER 2009 3. DATA ANALYSIS: Cross-Section (e,e’p) • For each kinematics, the cross-section is obtained as: Live time and Multitrack corrections Luminosity Solid angles Electron Energy Range • Using MCEEP we can simulate the Phase-space population and bin the acquired data in (pmiss,q,,) • Reduced cross-section was obtained as: CC1 - Prescription of De Forest Form Factors from J. Arrington fit of Rosenbluth data. PRC 69, 022201 (2004).

  32. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 12C(e,e’p) REDUCED CROSS-SECTION Simulations: RDWIA with and w/o relativistic dynamical effects in the wave function (projected) PRELIMINARY

  33. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 12C(e,e’p) REDUCED CROSS-SECTION COMPARATIVE WITH PREVIOUS EXPERIMENTS PRELIMINARY (*)

  34. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 12C(e,e’p) ATL PRELIMINARY

  35. HALL A COLLABORATION MEETING 16 DECEMBER 2009 SIMULATION DATA 4. RESULTS: Study of dependence with Q2 in 12C Reduced cross-section for the 1p32 shell (Emiss=[14-23] MeV)in 12C(e,e’p) are independent of Q2 No need to adjust simulation for the experiments at different Q2 within error bars (5%)

  36. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 208Pb(e,e’p) RED. CROSS-SECTIONCOMPARATIVE WITH PREVIOUS EXPERIMENTS

  37. HALL A COLLABORATION MEETING 16 DECEMBER 2009 4. RESULTS: 208Pb(e,e’p) ATL PRELIMINARY

  38. HALL A COLLABORATION MEETING 16 DECEMBER 2009 SIMULATION DATA 4. RESULTS: 208Pb(e,e’p)Study of dependence with Q2 in 208Pb Reduced cross-section for the valence states in 208Pb(e,e’p) are also independent of Q2

  39. HALL A COLLABORATION MEETING 16 DECEMBER 2009 5. CONCLUSIONS • Most of the data analysis of E06-007 experiment has already been done and preliminary results have been obtained. • In the last few months, we have focused on Bismuth data. CARBON and LEAD: • Results show no significant dependence of spectroscopic factors with Q2 both in Carbon and Lead. • Simulations obtained from just relativistic mean field calculations (without long-range correlations included) seem to compare fairly well with data at both low and high missing momentum and the ATL has the expected shape. • These results are being checked in more detail. Specially radiative corrections, systematic errors and different theoretical models. BISMUTH: • Cross-section for the state 1h9/2 has been obtained for different kinematics. These preliminary results are in fairly good agreement with RMF predictions with an occupancy of ~0.7 protons in that shell.

  40. HALL A COLLABORATION MEETING 16 DECEMBER 2009 With correlations Without correlations 2. THEORY AND SIMULATIONS Previous experiment at NIKHEF (Bobeldijk, PRL 1994) found an excess of strength at high pmiss in 208Pb(e,e’p). This was explained by two approaches: (1) Quasiparticle orbits plus non-relativistic DWIA. (2) Relativistic DWIA using independent particle orbit solutions to Dirac equation. The ATL is an excellent observable to check both models. Measuring the high pmiss region at the quasielastic peak with good statistics will reveal if long-range correlations are needed to describe the data. Non relativistic dynamics(Projected) Relativistic dynamics

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