The momentum broadening of energetic partons in an anisotropic plasma

TL;DR

This paper investigates how anisotropy in quark-gluon plasma affects the transverse momentum broadening of energetic partons, revealing significant differences from isotropic models and implications for jet-medium interactions.

Contribution

It provides a novel analysis of the anisotropic collision kernel for momentum broadening, highlighting qualitative differences from isotropic models and effects of increased medium screening.

Findings

Less transverse broadening at low and intermediate momenta due to increased screening.

Qualitatively different collision kernel compared to isotropic models.

Analysis applicable to both jet partons and quasiparticles in kinetic theory.

Abstract

The quark-gluon plasma produced in heavy-ion collisions is anisotropic throughout its evolution. This anisotropy changes the physics of jet-medium interaction, making it dependent on the momentum direction of the jet. In this paper we analyze transverse momentum broadening of a jet parton interacting with soft gluons in an anisotropic plasma. Our analysis equally applies to momentum broadening of quasiparticles in kinetic theory. We subtract contribution from instability modes in the deep infrared and discuss how our calculation should be complemented in that regime. The resulting anisotropic collision kernel for momentum broadening is qualitatively different from the equilibrium collision kernel and from the isotropic ansatz used in effective kinetic theory. Because of increased medium screening, there is substantially less transverse broadening at low and intermediate momenta.