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, 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.
@article{arxiv.2512.11951,
title = {Directional dead-cone effect in QCD matter},
author = {João Barata and Matvey V. Kuzmin and Xoán Mayo López and Andrey V. Sadofyev and Carlos A. Salgado},
journal= {arXiv preprint arXiv:2512.11951},
year = {2025}
}