Transport properties of bottomed mesons in a hot mesonic gas

TL;DR

This paper calculates the transport coefficients of B-mesons in a hot mesonic gas using chiral perturbation theory and unitarization, providing insights into heavy-flavor dynamics in heavy-ion collisions.

Contribution

It introduces a novel calculation of B-meson transport properties incorporating unitarized chiral amplitudes constrained by heavy quark symmetry.

Findings

Bottom relaxation length ~80 fm at 150 MeV and 1 GeV momentum

B mesons are cleaner probes of early heavy-ion collision stages than charm mesons

Results align with and extend previous literature on heavy-flavor diffusion

Abstract

In this work we evaluate the B-meson drag and diffusion coefficients in a hot medium constituted of light mesons (pions, kaons and eta mesons). We treat the B-meson and B*-meson interaction with pseudo-Goldstone bosons in chiral perturbation theory at next-to-leading order within the constraints from heavy quark symmetry, and employ standard unitarization techniques of NLO amplitudes in order to account for dynamically generated resonances (leading to a more efficient heavy-flavor diffusion) and thus reach higher temperatures. We estimate individual meson contributions from the gas to the transport coefficients and perform a comparison with other findings in literature. We report a bottom relaxation length of about 80 fm at a temperature of 150 MeV and for typical momenta of 1 GeV, at which our approach is reliable. Compared to a charm relaxation length of 40 fm in the same conditions, we conclude that the B mesons provide a cleaner probe of the early stages of a heavy-ion collision.