Heavy quark diffusion coefficient with gradient flow

Abstract

We calculate chromo-electric and chromo-magnetic correlators in quenched QCD at $1.5T_c$ and $10^4{T}_c$ with the aim to estimate the heavy quark diffusion coefficient at leading order in the inverse heavy quark mass expansion, ${\kappa }_E$, as well as the coefficient of first mass suppressed correction, ${\kappa }_B$. We use gradient flow for noise reduction. At $1.5T_c$ we obtain: $1.70\le {\kappa }_E/T^3\le 3.12$ and $1.03<{\kappa }_B/T^3<2.61$. The latter implies that the mass suppressed effects in the heavy quark diffusion coefficient are 20% for bottom quarks and 34% for charm quark at this temperature.

Comments: 18 pages, 20 figures, updated to match the published version