Paper detail

Production and energy loss of strange and heavy quarks

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 ($p_T$) and heavy flavor are thought to be well calibrated probes thus serve as ideal tools to study the properties of the medium. We present $p_T$ distributions of particle ratios in p+p collisions from STAR experiment to understand the particle production mechanisms. These measurements will also constrain fragmentation functions in hadron-hardon collisions. In heavy ion collsions, we highlight: 1) recent measurements of strange hadrons and heavy flavor decay electrons up to high $p_T$ to study jet interaction with the medium and explore partonic energy loss mechanisms; and 2) $Υ$ and high $p_T$ $J/ψ$ measurements to study the effect of color screening and other possible production mechanisms.