Color transparency (CT) in high momentum transfer (e,e’p→) and (e,e’p→) reactions is explored. The vector nature of the photon and the spin of the proton and photon are treated explicitly by describing the initial bound proton and the ejected wave packet as four-component Dirac spinors. Such effects, ignored in previous calculations, yield several results: (1) The use of Dirac-based optical potentials in the ‘‘standard calculation’’ (ignoring CT) leads to smaller cross sections than predicted before. (2) The normal component of the ejectile polarization, which vanishes in the limit of full CT, is found to approach zero very slowly as the energy increases. (3) Due to the presence of the 1${\mathit{H}}_{11/2}$ orbital, a measurement of the normal-transverse response in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ could afford the opportunity to see CT at quite low momentum transfers ∼1 GeV/c. (4) The four-component nature of our formalism allows us to determine that our calculations are roughly consistent with current conservation, except when the momentum of the struck nucleon is greater than about 150 MeV/c.

• Received 20 December 1993

DOI:https://doi.org/10.1103/PhysRevC.49.2747