Fluctuating Heavy Quark Energy Loss in Strongly-Coupled Quark-Gluon Plasma

TL;DR

This paper presents a novel energy loss model for heavy quarks in a strongly-coupled quark-gluon plasma that incorporates thermal fluctuations derived from string theory, improving agreement with experimental data from RHIC and LHC.

Contribution

It introduces the first model to include non-fluctuation-dissipation-based thermal fluctuations in heavy quark energy loss within AdS/CFT, enhancing data consistency.

Findings

Fluctuations are essential for matching RHIC and LHC data.

B meson and D meson anisotropies are similar at LHC.

The D to B meson nuclear modification factor ratio approaches unity faster than perturbative models.

Abstract

Results from an energy loss model that includes thermal fluctuations in the energy loss for heavy quarks in a strongly-coupled plasma are shown to be qualitatively consistent with single particle data from both RHIC and LHC. The model used is the first to properly include the fluctuations in heavy quark energy loss as derived in string theory and that do not obey the usual fluctuation-dissipation relations. These fluctuations are crucial for simultaneously describing both RHIC and LHC data; leading order drag results without fluctuations are falsified by current data. Including the fluctuations is non-trivial and relies on the Wong-Zakai theorem to fix the numerical Langevin implementation. The fluctuations lead to surprising results: B meson anisotropy is similar to that for D mesons at LHC, and the double ratio of D to B meson nuclear modification factors approaches unity more rapidly than even predictions from perturbative energy loss models. It is clear that future work in improving heavy quark energy loss calculations in AdS/CFT to include all energy loss channels is needed and warranted.