Ψ(2S) production in p + A collisions

Abstract

We have analyzed the data of ψ(2S) production in proton-nucleus (p + A) collisions, available from the NA50 Collaboration in the SPS energy domain. The investigated data sets include the absolute production cross-sections as well as ψ(2S)-to-Drell-Yan (DY) cross-section ratios. An adapted version of the two-component QVZ model has been employed to calculate ψ(2S) production cross-sections. For both ψ(2S) and DY production, nuclear modifications to the free nucleon structure functions are taken into account. For ψ(2S), the final state interaction of the produced pairs with the nuclear medium is also taken into account, in accordance with the previously analyzed data. A satisfactory description of the data in p + A collisions is obtained. Model calculations are extrapolated to predict the ψ(2S) suppression in proton-induced collisions at near-threshold energies.