  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.
