Proton propagation in nuclei studied in the<i>A</i>dependence of the (<i>e</i>,e’p) reaction in the quasifree region

Abstract

The A dependence of the (e,e'p) reaction in the quasifree region has been measured at an average ${Q}^{2}$ of 0.33 (GeV/c${)}^{2}$ for targets of $^{12}\mathrm{C}$, $^{27}\mathrm{Al}$, $^{58}\mathrm{Ni}$, and $^{181}\mathrm{Ta}$. The outgoing proton kinetic energy was 180\ifmmode\pm\else\textpm\fi{}30 MeV. By comparing the ratio of (e,e'p) coincidence to (e,e') singles yields, average proton transmissions are obtained for each target. The resulting ``mean free path'' or, more precisely, the attenuation length for protons in the nucleus is significantly longer than expectations based on the free nucleon-nucleon cross section.