Parton wakes and field angular momentum in chiral QCD plasma

Abstract

A fast parton moving through the quark-gluon plasma trails a wake of color fields, usually characterized through its screening cloud and the associated energy loss. Its behavior in a plasma carrying a chiral imbalance, set by a chiral chemical potential ${\mu }_5$, remains largely unexplored, in particular whether the imbalance induces a parity-odd component in the wake. We address this within chiral kinetic theory with Berry curvature corrections, at finite ${\mu }_5$ and zero magnetic field. The screening sector is found to be nearly insensitive to ${\mu }_5$, which enters only through the Debye mass. The chiral imprint resides instead in a parity-odd sector, comprising an azimuthal field encircling the parton, a poloidal chromo-magnetic field, and a circulating color current. All three are linear in ${\mu }_5$ and transverse to the velocity, and hence do no work on the parton. As the central result, these handed fields endow the wake with a net field angular momentum about the parton direction, odd in ${\mu }_5$ and of order $10^{-4}$--$10^{-3}\hslash$ per parton. The chiral medium thereby opens a parity-odd channel connecting hard probes to the chiral and vortical structure of the plasma.

Comments: 8 pages, 8 figures