J/{\Psi} and {\Psi}(2S) Production in p-Pb Collisions at 5.02 TeV with ATLAS

TL;DR

This paper reports on the measurement of J/Ψ and Ψ(2S) production in proton-lead collisions at 5.02 TeV, providing insights into cold nuclear matter effects and serving as a baseline for heavy-ion collision studies.

Contribution

It presents the first detailed measurement of prompt J/Ψ and Ψ(2S) nuclear modification factors and their double ratio in p-Pb collisions at the LHC, analyzing their dependence on multiple variables.

Findings

Nuclear modification factors indicate suppression or enhancement patterns.

Double ratio results suggest differences in Ψ(2S) and J/Ψ behavior.

Results help disentangle cold nuclear matter effects from hot medium effects.

Abstract

The production rates of heavy quarkonia in ion-ion collisions provide sensitive probes in the studies of the hot and dense matter formed in these collisions at high energies. However, a reference for understanding the behavior in the hot medium is necessary; p-A collisions open the possibility to study heavy quarkonia states in a smaller system of much lower average temperature. This is an important step in forming a baseline for understanding A-A collisions, as well as an investigation into the nature of modifications of the parton distributions in the nucleus. Using data collected at the LHC in 2013, we show results on the prompt J/{\Psi} and {\Psi}(2S) nuclear modification factors and the double ratio, {\Psi}(2S) divided by J/{\Psi} in p-Pb divided by the same in p-p, in p-Pb collisions at 5.02 TeV. The charmonia states were reconstructed via the dimuon decay channel and the yield is analyzed differentially in bins of transverse momentum, rapidity, and event activity.