Proton propagation in nuclei studied in the (e,e’p) reaction

Proton propagation in nuclei was studied using the ({ital e},{ital e}{prime}{ital p}) reaction in the quasifree region. The coincidence ({ital e},{ital e}{prime}{ital p}) cross sections were measured at an electron angle of 50.4{degree} and proton angles of 50.1{degree}, 58.2{degree}, 67.9{degree}, and 72.9{degree} for {sup 12}C, {sup 27}Al, {sup 58}Ni, and {sup 181}Ta targets at a beam energy of 779.5 MeV. The average outgoing proton energy was 180 MeV. The ratio of the ({ital e},{ital e}{prime}{ital p}) yield to the simultaneously measured ({ital e},{ital e}{prime}) yield was compared to that calculated in the plane-wave impulse approximation and an experimental transmission defined. These experimental transmissions are considerably larger (a factor of {similar to}2 for {sup 181}Ta) than those one would calculate from the free {ital N}-{ital N} cross sections folded into the nuclear density distribution. A new calculation that includes medium effects ({ital N}-{ital N} correlations, density dependence of the {ital N}-{ital N} cross sections and Pauli suppression) accounts for this increase.