Quenching jets increases their flavor

Abstract

The widespread notion that jets quenched in a Quark-Gluon-Plasma (QGP) are similar in their parton flavor composition to jets in vacuum is critically examined. We demonstrate that while the soft to semi-hard [low to intermediate transverse momentum ($p_T$)] sector of vacuum jets are predominantly bosonic i.e., composed of gluons, \emph{sufficiently} quenched jets can have an intermediate momentum sector that is predominantly fermionic, dominated by quarks and antiquarks. We demonstrate, using leading order perturbative QCD processes, that the rate of flavor conversion from a gluon traversing the QGP as part of a jet, to a quark or antiquark, versus the reverse process, grows steadily with falling $p_T$. Simple diagrammatic estimates are followed by a variety of realistic simulations in static media. The relation of this increase in flavor to the observed baryon enhancement at intermediate $p_T$ is studied in a fully realistic simulation.