The Experiment

The experiment consists of making measurements of the cross section for the reaction 4He(e,e'p)3H. These measurements are made for missing momenta in the vicinity of 430 MeV/c, where most modern calculations predict that the overlap amplitude crosses zero; thus at least in plane wave approximation, the (e,e'p) cross section should go to zero at some point near 430 MeV/c. The structure of this predicted minimum is sensititive to short-range structure in 4He.

Conversely, if the cross section does not go to zero, whatever cross section we measure should be "all" contaminant, e.g. final state interaction, meson exchange current, etc. So this experiment has elements of both nuclear structure research as well as nuclear reaction mechanism study.

This experiment was motivated by the results of experiment 91-10 at NIKHEF (performed in 1994, see links below of van Leeuwe et al.), in which several of us have participated. The results of that experiment have already been published. See the literature section immediately following.

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The Proposal

Meetings, Collaboration, Contacts

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• Minutes for the meeting on July 24, 2000.

Working Documents

• The most recent run plan. Last updated 11:54 on October 15. This document has now been updated to include lots of the on-shift tasks directed towards verifying the data.
• We got different beam energies than for which we asked. This document outlines new kinematic settings and rates based on the beam energies we did get. Last Updated: Wed Jul 19 16:43:19 EDT 2000
• The most recent version of the todo list. Last updated Fri Jul 21 13:39:13 EDT 2000.
• The original todo list for the experiment. The date says July 7th but this is a lie; it was actually constructed on March 7th 2000.

Talks

• Templon talk at June 2000 E97-111 Meeting
• Templon talk at May 2000 Hall A Collaboration Meeting
• PAC Defense talk (January 1998).
• Templon talk at November 1997 Few-Body Working Group Meeting

Literature (Physics Motivation, Other Experiments, etc.)

Most Recent Links and References

• O. Benhar et al., final state interactions in 4He(e,e'p)3H at large proton energy, available online.
• A. Kozlov et al., the longitudinal and transverse response of the 4He(e,e'p) reaction in the dip region, from Few-Body 1999 proceedings, available online.
• S. A. Sofianos, G. Ellerkmann, W. Sandhas, integral equation results for the 4He(e,e'p)3H reaction at high missing momenta, available online.
• V.D. Efros, W. Leidemann, G. Orlandini, E.L. Tomusiak, Electromagnetic response functions of few-nucleon systems, available online.
• J. A. Templon, studying short range dynamics in few body systems, Fizika B8 (1999) 117. available online.
• H. Morita, C. Ciofi degli Atti, D. Treleani, a realistic study of the nuclear transparency and the distorted momentum distributions in the semi-inclusive process 4He(e,e'p)X, available online.
• R. Guardiola, M. Portesi, state-dependent jastrow correlation functions for 4He nuclei, available online.
• A.Bianconi, S.Jeschonnek, N.N.Nikolaev and B.G.Zakharov, do final state interactions obscure short range correlation effects in quasielastic A(e,e'p) scattering?, Nucl. Phys. A608, (1996) 437; erratum Nucl. Phys. A616, (1997) 680, available online.

Links pertaining to NIKHEF '94 Experiment

• Investigation of nucleon-nucleon correlations in 4He, Ph.D. Thesis of J. J. van Leeuwe, NIKHEF/UvA 1996.
• J. J. van Leeuwe et al., The 4He(e,e'p) cross section at large missing energy Talk given by J. Templon at the 15th International Conference on Few-Body Problems in Physics (FB 97), Groningen, Netherlands, 22-26 July 1997. Published in Nucl. Phys. A631 (1998) 593c. available electronically.
• J. J. van Leeuwe et al., high missing momentum components in 4He studied with the (e,e'p) reaction, Phys. Rev. Lett. 80 (1998) 2543.

Before NIKHEF '94 Experiment

This set of links has been compiled from the literature search in Koos van Leeuwe's PhD thesis.

Here you can find a list from SPIRES of articles which reference the 1988 PRL article of van den Brand et al.

• V. A. Goldstein et al., Nucl. Phys. A335 (1981) 333. (Kharkov data)
• "The two-body electrodisintegration of 4He studied through the (e,e'X) reaction", Ph.D. Thesis of J. F. J. van den Brand, NIKHEF/UvA 1988.
• J. F. J. van den Brand et al., Phys. Rev. Lett. 60 (1988) 2006. (NIKHEF data)
• J. F. J. van den Brand et al., Nucl. Phys. A534 (1991) 637. (NIKHEF data)
• J. F. J. van den Brand et al., Phys. Rev. Lett. 66 (1991) 409. (NIKHEF data)
• J. E. Ducret et al., Nucl. Phys. A556 (1993) 373. (Saclay data)
• J. M. LeGoff et al., Phys. Rev. C50 (1994) 2278. (Saclay data)