Do nucleons that are bound in nuclei change their structure?
Polarization transfer in quasi-elastic nucleon knockout is sensitive to the properties of the nucleon in the nuclear medium, including possible modification of the nucleon form factor and/or spinor. Recent measurements at both Mainz and Jefferson Lab of the proton recoil polarization in the {sup 4}He({rvec e},e'{rvec p}){sup 3}H reaction up to Q{sup 2} = 2.6 (GeV/c){sup 2} are presented. The measured ratio of polarization-transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model. In addition, the measured induced polarizations agree reasonably well with the fully relativistic calculation, indicating that the treatment of final-state interactions is under control. A recently approved follow-up experiment at a Q{sup 2} of 0.8 (GeV/c){sup 2} and 1.3 (GeV/c){sup 2} with unprecedented precision will provide one of the most stringent tests of the applicability of these calculations.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE - Office of Energy Research (ER)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 883648
- Report Number(s):
- JLAB-PHY-04-71; DOE/ER/40150-3933; TRN: US0603532
- Resource Relation:
- Conference: 32nd International Workshop on Gross Properties of Nuclei and Nuclear Excitation: Probing Nuclei and Nucleons with Electrons and Photons (Hirschegg 2004), Hirschegg, Austria, 11-17 Jan 2004
- Country of Publication:
- United States
- Language:
- English
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