STAR Overview of Hard Probe Observables

TL;DR

This paper reviews STAR experiment results on hard probes like jets, quarkonium, and electromagnetic particles, shedding light on Quark-Gluon Plasma properties through diverse measurements at RHIC.

Contribution

It provides an overview of recent STAR measurements on jets, quarkonium, and electromagnetic probes, highlighting new detector performance and specific results in heavy-ion and proton-proton collisions.

Findings

Jets and $$ measurements in Au+Au collisions reveal energy loss effects.

$J/$ production in p+p collisions at 500 GeV shows baseline behavior.

Low mass di-electron spectrum indicates potential medium modifications.

Abstract

Parton energy loss, quarkonium sequential melting and particle production from electromagnetic interactions are tools to study Quark Gluon Plasma properties. The STAR detector, with large acceptance at mid-rapidity, excellent particle identification and wide transverse momentum coverage, is able to study these probes in details. In Hard Probes 2015, the STAR collaboration reported measurements of reconstructed jets, heavy-flavor physics, di-lepton production and the performance of new detectors in seven presentations and one poster. Given the rich results from STAR, this overview report will focus on a few selected results on jets and $\Upsilon$ measurements in Au+Au collisions at $\sqrt{s_{\rm NN}}=200\,$GeV, $J/\psi$ production in $p$+$p$ collisions at $\sqrt{s_{\rm NN}}=500\,$GeV, and the di-electron spectrum in the low mass region from the Beam Energy Scan - Phase I.