Quarkonium Production and Medium Effects in High Energy Nuclear Collisions

TL;DR

This paper discusses how color screening and regeneration influence quarkonium production in high energy nuclear collisions, highlighting that transverse momentum measurements can reveal properties of the quark-gluon plasma.

Contribution

It introduces the importance of transverse momentum analysis to distinguish medium effects on quarkonium production in nuclear collisions.

Findings

The integrated quarkonium yield ratio loses sensitivity due to competing effects.

Transverse momentum squared ratio provides insights into the QCD medium.

Medium effects can be disentangled through transverse motion analysis.

Abstract

Color screening and regeneration are both hot medium effects on quarkonium production in high energy nuclear collisions. However, they affect in an opposite way the finally observed quarkonium spectra. Due to the competition of the two dynamical effects, the ratio of the integrated quarkonium yield between nuclear and elementary nucleon collisions loses its sensitivity. Once the information of quarkonium transverse motion is included, on the other hand, the ratio of averaged transverse momentum square reveals the nature of the QCD medium created in high energy nuclear collisions.