Search for Proton Medium Modifications in the 4He(e,e'p)3H Reaction
arXiv:0709.4034 · doi:10.1063/1.2834464
Abstract
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. In our recently completed experiment E03-104 at Jefferson Lab we measured the proton recoil polarization in the 4He(e,e'p)3H reaction at a Q^2 of 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2 with unprecedented precision. These data complement earlier data between 0.4 and 2.6 (GeV/c)^2 from both Mainz and Jefferson Lab. The measured ratio of polarization-transfer coefficients differs from a fully relativistic calculation, favoring either the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model or strong charge-exchange final-state interactions. The measured induced polarizations agree well with the fully relativistic calculation and indicate that these strong final-state interactions may not be applicable.
Proceedings prepared for the Fifth International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt07), May 30-June 2, 2007. Proceedings to be published by the AIP (6 pages)