Color transparency and spin effects in (e,e'rvec p) reactions

Color transparency (CT) in high Q2 (e,e'rvec p) reactions is explored. The spin of the proton and photon are treated explicitly by describing the initial bound proton and the ejected wavepacket as 4-component Dirac spinors. Such effects, ignored in previous calculations, yield several main results: (1) The use of Dirac-based optical potentials, ignoring CT, leads to smaller cross sections than predicted before; (2) The normal component of the ejectile polarization Pn, which vanishes in the limit of full CT, is found to approach zero very slowly with increasing energy; (3) A measurement of the normal-transverse response RnT in 208Pb may afford the opportunity to see CT at Q2∼4 GeV2. copyright 1995 American Institute of Physics