J/$\psi$ and $\psi$(2S) production in p-Pb collisions with ALICE at the LHC

TL;DR

This paper reports on measurements of J/ψ and ψ(2S) production in proton-lead collisions at the LHC, showing agreement with theoretical models and highlighting differences in nuclear modification between the two states.

Contribution

First measurement of ψ(2S) production in p-Pb collisions at the LHC, comparing its nuclear modification to J/ψ and testing theoretical models.

Findings

J/ψ production agrees with nuclear shadowing and energy loss models.

ψ(2S) shows a smaller nuclear modification factor than J/ψ.

Results provide insights into quarkonium production in nuclear environments.

Abstract

The ALICE collaboration has studied the inclusive J/$\psi$ and $\psi(\mathrm{2S})$ production in p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV at the CERN LHC. The J/$\psi$ measurement is performed in the $\mu^{+}\mu^{-}$ ( - 4.46 < $y_{cms}$ < - 2.96 and 2.03 < $y_{cms}$ < 3.53 ) and in the $e^{+}e^{-}$ ( - 1.37 < $y_{cms}$ < 0.46 ) decay channels, down to zero transverse momentum. The results are in fair agreement with theoretical predictions based on nuclear shadowing, as well as with models including, in addition, a contribution from partonic energy loss. Finally, the $\psi(\mathrm{2S})$ measurement in the $\mu^{+}\mu^{-}$ decay channel has been performed. In particular, a significantly smaller $\psi(\mathrm{2S})$ nuclear modification factor, with respect to the J$/\psi$ one, has been observed.