Quarkonia Measurements with STAR

TL;DR

This paper presents measurements of quarkonium production at RHIC, including J/psi spectra, nuclear modification factors, and correlations, providing insights into production mechanisms and future experimental prospects.

Contribution

It reports the first high-p_T J/psi-hadron correlation measurements at RHIC and discusses implications for quarkonium production and suppression mechanisms.

Findings

J/psi yields at high p_T are consistent in p+p and scaled Cu+Cu collisions.

Nuclear modification factor R_AA for J/psi is approximately 0.9.

First measurements of high-p_T J/psi-hadron correlations at RHIC.

Abstract

We report results on quarkonium production from the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). J/psi spectra in p+p and Cu+Cu collisions at sqrt(s) = 200 GeV with transverse momenta in the range of 0.5-14 GeV/c and 5-8 GeV/c, respectively, are presented. We find that for p_T > 5 GeV/c yields in p+p collisions are consistent with those in minimum-bias Cu+Cu collisions scaled with the respective number of binary nucleon-nucleon collisions. In this range the nuclear modification factor, R_AA, is measured to be 0.9+-0.2(stat). For the first time at RHIC, high-p_T J/psi-hadron correlations were studied in p+p collisions. Implications from our measurements on J/psi production mechanisms, constraints on open bottom yields, and J/psi dissociation mechanisms at high-p_T are discussed. In addition, we give a brief status of measurements of Upsilon production in p+p and Au+Au collisions and present projections of future quarkonia measurements based on an upgrades to the STAR detector and increased luminosity achieved through stochastic cooling of RHIC.