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

TL;DR

This paper reports on measurements of inclusive J/ψ and ψ(2S) production in proton-proton and proton-lead collisions at the LHC, providing new differential cross-sections, production ratios, and nuclear modification factors at forward rapidity.

Contribution

It presents the first extended transverse momentum measurements of J/ψ and ψ(2S) production at forward rapidity in pp collisions and compares these with previous ALICE and LHCb results, also including p-Pb collision analysis.

Findings

Extended pT reach of J/ψ and ψ(2S) measurements.

Measured ψ(2S)/J/ψ production ratio as a function of pT and y.

Determined nuclear modification factors and forward-to-backward ratios in p-Pb collisions.

Abstract

The ALICE collaboration has studied inclusive J/$\psi$ and $\psi$(2S) production at forward rapidities in pp collisions at $\sqrt{s} = 7$ TeV with the ALICE Muon Spectrometer. The analysis has been carried out on a data sample corresponding to an integrated luminosity $\mathcal{L}_{\rm int}$ = 1.35 pb$^{-1}$. The production cross-sections of J/$\psi$ and $\psi$(2S), integrated over the transverse momentum (0 $<$ $p_{{\mathrm T}}$ $<$ 20 GeV/$c$) and rapidity (2.5 $<$ $y$ $<$ 4), have been measured. The J/$\psi$ and $\psi$(2S) differential cross-sections, in transverse momentum and rapidity, have also been measured, significantly extending the $p_{{\mathrm T}}$ reach of previous measurements performed in the same $y$-range. The results have been compared with the previously published ALICE results ($\mathcal{L}_{\rm int}$ = 15.6 nb$^{-1}$) and also with the measurement performed by the LHCb collaboration. The $\psi$(2S)/J/$\psi$ ratio, integrated over $p_{{\mathrm T}}$ and $y$, has been measured. This ratio has also been evaluated as a function of transverse momentum and rapidity and compared with the LHCb measurement. Finally, recent results on cross-sections, $\psi$(2S)/J/$\psi$ production ratio, nuclear modification factor ($R_{\rm pPb}$) and forward-to-backward yield ratio ($R_{\rm FB}$) in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV will be discussed.