Nuclear effects in the hadroproduction and photoproduction of J/ψ

Abstract

Hadroprduction of J/ψ in π_- nucleus collisions is studied in the context of the colour singlet model using nuclear structure functions from three different models of the EMC effect. We conclude that it is possible to understand the data on the large transverse momentum (p_T ) and small Feynman x (x_F ) of the J/ψ in terms of the nuclear dependence of structure functions alone. We further show that these data can be used to distinguish between different models of the EMC effect, and that a study of distributions in various kinematic variables in photoproduction of J/ψ should be able to very effectively supplement the information obtained from hadroproduction experiments.