Progress Towards Understanding Quarkonia at PHENIX

TL;DR

This paper reviews PHENIX's recent measurements of quarkonia production in various collision systems, highlighting insights into gluon distributions, cold nuclear matter effects, and suppression patterns in hot-dense nuclear matter.

Contribution

It provides new experimental data on quarkonia production in p+p, d+Au, and nucleus-nucleus collisions, advancing understanding of CNM effects and quarkonia suppression mechanisms.

Findings

Observation of quarkonia suppression patterns in nucleus-nucleus collisions.

Measurement of cold nuclear matter effects in d+Au collisions.

New data from PHENIX's 2007-2008 run.

Abstract

Quarkonia (J/psi, psi', chi_C, Upsilon) production provides a sensitive probe of gluon distributions and their modification in nuclei; and is a leading probe of the hot-dense (deconfined) matter created in high-energy collisions of heavy ions. We will discuss the physics of quarkonia production in the context of recent p+p measurements at PHENIX. We next discuss Cold-Nuclear Matter (CNM) effects as seen in our measurements in $d+Au$ collisions - both for intrinsic physics such as gluon saturation and final-state dissociation, and as a baseline for studies in nucleus-nucleus collisions. Then we review the latest nucleus-nucleus results in the light of the expected CNM effects, and discuss two leading scenarios for the observed suppression patterns. Finally we show the latest data from PHENIX, including new d+Au data from the 2007-2008 run; and then look into the future.