Mesonic and binding contributions to the nuclear Drell-Yan process

We have evaluated the Drell-Yan cross section in nuclei paying special atte ntion to the meson cloud contribution from pions and rho-mesons, for which an accurate calculation using the meson nuclear spectral functions is used. Similarly, the nucleonic contribution is evaluated in terms of a relativis tic nucleon spectral function. Fair agreement with experiment is found for different nuclei and the results show a sizeable contribution from the reno rmalized meson cloud. In order to reproduce the experiment a novel element is introduced, consisting of a gradual energy loss of the incoming proton i n its pass through the nucleus which produces a strong A dependence at x(1) large. (C) 1999 Elsevier Science B.V.