Dissociation of large transverse-momentum prompt J/psi produced in Pb-Pb collisions at the LHC

TL;DR

This paper investigates the suppression of prompt J/psi particles at high transverse momentum in Pb-Pb collisions at the LHC, proposing a mechanism involving meson-charmonium interactions and calculating dissociation rates.

Contribution

It introduces a new model for prompt J/psi suppression based on meson-charmonium interactions and provides quantitative dissociation rates relevant for high transverse momentum.

Findings

Dissociation rate decreases with increasing transverse momentum.

The model explains the observed nuclear modification factor trend.

Cross sections for pion-charmonium reactions are parametrized and used in calculations.

Abstract

A collision of a light meson and a charmonium produces quarks and antiquarks first, then the charm quark fragments into a charmed hadron, and finally three or more mesons are produced. This is the mechanism that we consider and propose to understand the prompt-J/psi nuclear modification factor in the range of J/psi transverse momentum from 10 GeV/c to 18 GeV/c, as measured by the CMS Collaboration and the ATLAS Collaboration. Unpolarized cross sections are derived and calculated for the reactions pion+charmonium ->H_c+X with H_c being a charmed meson. Numerical cross sections are parametrized and used to calculate the dissociation rate of charmonium in the interaction with pions in hadronic matter. The momentum dependence of the rate obtained is so as to lead to a decreasing charmonium nuclear modification factor with increasing transverse momentum.