Directional dead-cone effect in QCD matter

TL;DR

This paper investigates how heavy quarks interact with a flowing quark-gluon plasma, revealing a directional dead-cone effect and a tensorial jet transport coefficient that influence jet quenching and radiation patterns.

Contribution

It introduces the tensorial jet transport coefficient and the directional dead-cone effect, highlighting their roles in heavy quark propagation in a flowing QCD medium.

Findings

Identification of a tensorial jet transport coefficient, $_{ij}$.

Discovery of the directional dead-cone effect causing anisotropic radiation suppression.

Discussion of observable signatures in jet measurements.

Abstract

We consider the propagation of heavy quarks through a dense, hydrodynamically flowing QCD medium, representative of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions. Working in the high-energy limit, we identify two novel mass-dependent effects arising from the heavy quark coupling to the local medium flow. The first is the emergence of a tensorial jet transport coefficient, $\hat{q}_{ij}$, which encodes the directional structure of transverse-momentum broadening. The second, named the directional dead-cone effect, corresponds to an anisotropic suppression of medium-induced radiation aligned with the hydrodynamic flow. We discuss how these effects manifest in jet observables and identify distinctive signature of heavy quark dynamics in an evolving medium.