Production and energy loss of strange and heavy quarks

Abstract

Data taken over the last several years have demonstrated that RHIC has created a hot, dense medium with partonic degrees of freedom. Identified particle spectra at high transverse momentum (pT) and heavy flavor that are thought to be well-calibrated probes thus serve as ideal tools to study the properties of the medium. We present pT distributions of particle ratios in p+p collisions from the STAR experiment to understand the particle production mechanisms. These measurements will also constrain fragmentation functions in hadron–hardon collisions. In heavy-ion collisions, we highlight (1) recent measurements of strange hadrons and heavy flavor decay electrons up to high pT to study jet interaction with the medium and explore partonic energy loss mechanisms, and (2) ϒ and high pT J/ψ measurements to study the effect of color screening and other possible production mechanisms.