Attenuation of ϕ mesons in γA reactions

We present a theoretical analysis of inclusive photoproduction of ϕ mesons in nuclei. In particular the dependence of the total ϕ meson yield on the target mass number is investigated. The calculations are done using the semi-classical BUU transport approach that combines the initial state interaction of the incoming photon with the coupled-channel dynamics of the final state particles. The conditions of the calculations are chosen such as to match the set-up of a recent experiment performed at SPring8/Osaka. Whereas the observables prove to be rather sensitive to the ϕ self energy in the medium, the attribution of deviations from the standard scenario to a particular in-medium effect seems to be impossible.