4 He(e,e'p)X, April 13 and April 14, 2011, 16 hours Measured P miss at 0.153 to 1.0 GeV/c, x b =...
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Transcript of 4 He(e,e'p)X, April 13 and April 14, 2011, 16 hours Measured P miss at 0.153 to 1.0 GeV/c, x b =...
4He(e,e'p)X, April 13 and April 14, 2011, 16 hoursMeasured Pmiss at 0.153 to 1.0 GeV/c, xb = 1.24, Q2 = 2
(GeV/c)2
• Extension of SRC 2 body data which measured Pmiss from 0.4 to 1 GeV/c
• Actual target thickness(20 cm), 20 K at 10 atm = 1x1023/cm3
• Target thickness from proposal(10cm) 6 K at 10 atm = 1.24x1023/cm3
Students: S. Iqbal(CSULA), N. McMahon(CNU)Spokespersons: A. Saha, D. Higinbotham, F. Benmokhtar, S. Gilad, K. AniolHall A Collaboration Experiment
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Motivation – Cross sections for 4He(e,e'p)3H, xb=1.25
and Nucleon Correlations4He is fundamental for nuclear microscopic theory. Theory must include many body forces for the 4 body system.
First measurement of 4He(e,e'p)X at this value of xb >1.
Theory should be able to account for all the nucleon channels.X = 3H, n+2H, n+n+p
Compare to theoretical cross sections (4He(e,e'p)3H, xb=1.25)
Compare to F. Benmokhtar results at 3He(e,e'p)X (xb =1) for 2 body
absorption peak in continuum.
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755 MeV/c
625 MeV/c
500 MeV/c
380 MeV/c
150 MeV/c
800 MeV/cUnder analysis
0.153 GeV/c
0.353 GeV/c
0.500 GeV/c
0.625 GeV/c
0.755 GeV/c
0.800 GeV/c
4He(e,e'p)XMissing Energy
For central kinematics
triton
2 body absorption
Steps in the Analysis for 4He(e,e'p)3H
We have overlapping missing momentum bins for 0.153 and 0.353 GeV/c kinematic settings
Divide missing momentum into 50 MeV/c bins in data
Divide missing momentum into 50 MeV/c bins in simulation
Compare data from two kinematic settings using simulation
Efficiencies TBD e.g. dead time, acceptances, target density and beam heating effects, match (w,q) cuts
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Preliminary triton yields/electron - Simulation assumes uniform illumination of spectrometer apertures.Have received theory RDWA from MadridNext step to include theory in simulation.
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Emiss (MeV)
F. Benmokhtar, et al. E89044Phys.Rev.Lett.94:082305,2005
3He(e,e'p)X, Q2=1.55 GeV2, xb = 1
Similar 2 body absorption seen in 3He – needs 3bbu to fit cross section
Next StepsGet experimental cross sections• Get more theory calculations for 2 body.We have Madrid’scalculations now
• Need theory for 3 body. We have promises.
• Extract the Effective Density and compare to 3He.
See if there is scaling!
4He(e,e'p)X xb = 1.25, Q2 = 2 (GeV/c)2
0.755 GeV/c
0.625 GeV/c
0.500 GeV/c
0.353 GeV/c
0.153 GeV/c
LE
miss
Extra Slides for backup
Semi-Inclusive A(e,e’p)Xprobes a p-n pair?
-Pm
p = q-Pm
q,
Pm
e
e’
3He(e,e'p)X, Q2=1.55 GeV2, xb = 1 Jlab-E89044 Hall A experiment.
Example:
Missing Energy
Effective Density Distribution 3He(e,e'p)X, Q2=1.55 GeV2, xb = 1
-J. M. Laget Calculations (Fadeev WF and Paris Potential ( diagramatic approach)-Also available are calculations from C. degli-Atti et al., using realistic wave function with generalized Eikonal approximation for FSI.
-Conclusions: Both Correlations in initial state and Final State Interactions play a role in this strength .