Photoproduction of η′ mesons from nuclei and their properties in the nuclear medium

Abstract

We study the photoproduction of η′ mesons from nuclei near the threshold within the collision model based on the nuclear spectral function. The model properly takes into account both the primary photon–nucleon γN → η′N and the secondary pion–nucleon πN → η′N production processes as well as the effect of the nuclear η′ mean-field potential on these processes. We find that the secondary channel πN → η′N plays an insignificant role in the η′ photoproduction from nuclei. We calculate the transparency ratio for η′ mesons and compare it to the available experimental data. The comparison indicates an inelastic η′N cross section of the order of 6–10 mb. We show that the existing transparency ratio measurements do not allow one to distinguish between two adopted η′ in-medium modification scenarios. Our studies also demonstrate that the momentum distribution and excitation function for η′ production in γA reactions reveal some sensitivity to these scenarios, which means that such observables may be an important tool to get valuable information on the η′ in-medium properties.