Effect of $NN$-correlations on predictions of nuclear transparencies for protons, knocked-out in high $Q^2\,(e,e'p)$ reactions

Abstract

We study the transparency $\cal T$ of nuclei for nucleons knocked-out in high-energy semi-inclusive $(e,e'p)$ reactions, using an improved theoretical input, discussed by Nikolaev et al. We establish that neglect of $NN$-correlations between the knocked-out and core nucleons reduces nuclear transparencies by $\approx 15 \%$ for light, to $\approx 10\%$ for heavy nuclei. About the same is predicted for transparencies, integrated over the transverse or longitudinal momentum of the outgoing proton. Hadron dynamics predicts a roughly constant $\cal T$ beyond $Q^2\approx $2 GeV$^2$, whereas for all targets the largest measured data point $Q^2$=6.7 GeV$^2$ appears to lie above that plateau. Large error bars on those data-points preclude a conclusion regarding the onset of colour transparency.