# J/$\psi$ production as a function of charged-particle pseudorapidity density in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

## TL;DR

This paper measures how J/$\\psi$ production varies with charged-particle density in p-Pb collisions at 5.02 TeV, revealing saturation effects and rapidity-dependent suppression patterns.

## Contribution

It provides the first detailed analysis of J/$\psi$ yield and transverse momentum dependence on charged-particle density across different rapidities in p-Pb collisions.

## Key findings

- J/$\psi$ yield increases with multiplicity at mid and backward rapidities.
- Saturation of J/$\psi$ yield occurs at high multiplicities at forward rapidity.
- Forward-to-backward suppression ratio increases with multiplicity.

## Abstract

We report measurements of the inclusive J/$\psi$ yield and average transverse momentum as a function of charged-particle pseudorapidity density ${\rm d}N_{\rm ch}/{\rm d}\eta$ in p-Pb collisions at $\sqrt{s_{\rm NN}}= 5.02$ TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/$\psi$ yield with normalised ${\rm d}N_{\rm ch}/{\rm d}\eta$, measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/$\psi$ production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity.