Charmonium and open-charm production in proton–nucleus collisions at the CERN SPS

Abstract

p–A collisions provide an essential reference for the study of J/ψ suppression in heavy-ion interactions since they allow us to evaluate cold nuclear matter (CNM) effects. These include initial state effects, such as shadowing and parton energy loss, and final state effects such as J/ψ breakup in the collisions with nucleons. To evaluate these effects, NA60 has measured J/ψ production in p–A collisions with seven nuclear targets at GeV and, for the first time, at the same of Pb–Pb and In–In SPS data: 17.3 GeV. More recently, open-charm production has also been studied by analysing the dimuon continuum generated by the simultaneous semi-muonic decay of D meson pairs. The comparison of the production of closed charm with its natural reference (open charm) can give some insight on how the interplay of the different CNM effects produces the observed (effective) J/ψ suppression.