 4 He(e,e'p)X, April 13 and April 14, 2011, 16 hours Measured P miss at and GeV/c, x b = 1.24, Q 2 = 2 (GeV/c) 2 Extension of SRC 2 body data which measured P miss from 0.4 to 1 GeV/c Actual target thickness(20 cm), 20 K at 10 atm = 1x10 23 /cm 3 Target thickness from proposal(10cm) 6 K at 10 atm = 1.24x10 23 /cm 3 Discussion of data we collected follows Students: S. Iqbal(CSULA), N. McMahon(CNU) Spokespersons: A. Saha, D. Higinbotham, F. Benmokhtar, S. Gilad, K. Aniol Hall A Collaboration Experiment 1

Motivation – Nucleon Correlations Compare to Benmokhtar results at 3 He(e,e'p)X (x b =1). Can also compare to Monaghan( 12 C(e,e'p)X, SRC) 4 He is the next step for microscopic theory with the 4 body system. 4 He(e,e'p)X is one component of the interpretation of the SRC data. Theory should be able to account for all the nucleon channels. X = 3 H, n+ 2 H, n+n+p First measurement of 4 He(e,e'p)X at this value of x b >1. 2

E miss (MeV) Search for correlations in continuum data F. Benmokhtar, et al. E89044 Integrate over Pmiss and follow quasi deuteron absorption peak Earlier work by J. M. Legoff et al, For 4 He(e,e'p)X PRC (1994), Q 2 = 0.04 GeV 2, x = 0.14 also found a peak in the E miss spectrum that followed the kinematics for absorption on a 2 nucleon pair. Earlier work by J. M. Legoff et al, For PRC (1994), Q2 = 0.04 GeV 2, x = 0.14 also found a peak in the Emiss spectrum that followed the kinematis for absorption on a 2 nucleon pair. Phys.Rev.Lett.94:082305,2005 Measurement of the He-3(e,e-prime p)pn reaction at high missing energies and momenta. 3 He(e,e'p)X, Q 2 =1.55 GeV 2, x b = 1 3

length = 20cm T = 20K P = 10atm Density = 1x10 23 nuclei/cm 3 ? Ztgt in meters Event vertex along beam axis 4

Missing Momenta, GeV/c setting, normalized to equal counts Data, 4 He(e,e'p)X 4 He(e,e'p) 3 H, only kinematical and energy loss effects Theory must still be added to simulation! GeV/c Missing Momenta, Data vs GEANT(phase space) 5

Missing energy, GeV/c setting 4 He(e,e'p) 3 H, only kinematical and energy loss effects geant Data, 4 He(e,e'p)X Qvalue to 3 H ground state MeV 3 H gs 100 MeV GeV Missing Energy, Data vs GEANT(phase space) 6

P miss vs E miss, GeV/c setting GeV GeV/c 7

0.153 GeV/c GeV/c P miss GeV/c DATA Comparison of missing momenta coverage for the two low P miss kinematic settings Normalized to equal counts 4 He(e,e'p)X, x b = 1.24, Q 2 = 2 (GeV/C) 2 Missing Momenta 8

Coincidence time for GeV/c setting 7 ns Coincidence time Coincidence Time 9

Geant, 4 He(e,e'p) 3 H 4 He(e,e'p)X Comparison of data and geant phase space simulation GeV/c GeV/c setting Missing Momentum, data vs GEANT 10

E miss GeV GeV/c P miss GeV/c Setting GeV, Emiss 3 H gs P miss 11

GeV 4 He(e,e'p)X Geant, 4 He(e,e'p) 3 H Full P miss Geant, 4 He(e,e'p) 3 H P miss <0.3 GeV/c Geant, 4 He(e,e'p) 3 H P miss <0.25 GeV/c x b = 1.24, Q 2 = 2 (GeV/C) 2, P miss = GeV/c setting Comparison of data to various GEANT cuts based on Pmiss acceptance in GEANT * * LeGoff prediction for E miss for quasi deuteron scattering 12

GeV Cut on 0.2<Pmiss<0.3 GeV/c P miss GeV/c setting Missing Energy 3 H, gs DATA 13

GeV Cut on 0.3<Pmiss<0.4 GeV/c P miss GeV/c setting Missing Energy 3 H, gs 14

P miss, GeV/C Missing Momenta Coverage Kinematic settings GeV/c GeV/c GeV/c

Missing Energy Emiss, GeV Missing Energy Spectrum for GeV/C kinematic setting * LeGoff prediction for E miss for quasi deuteron scattering * 16

1) From the difference between the phase space GEANT simulations for P miss and E miss compared to the data, the data favor low values of P miss. Theory must enhance the low P miss cross sections. A Conclusion is possible even before the theory is included in simulations. 2) The LeGoff prediction for the peak location in E miss is consistent with the spectra at and GeV/c. 17

Next steps: Still have data at 0.625, and GeV/c Finalize the cuts Get cross sections Get more theory calculations for 2 body(We have Madrid calculations now) Need theory for 3 body and 4 body breakup Simulate theory in GEANT 18

BACKUP SLIDES 19

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0.353 GeV/c setting 4 He(e,e'p)X, data 4He(e,e'p), geant GeV 21

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