Medium effects on heavy-flavour observables in high-energy nuclear collisions

TL;DR

This paper discusses how heavy-flavour particles produced in high-energy nuclear collisions interact with and are affected by the hot deconfined medium, highlighting a comprehensive transport approach and implications for small systems.

Contribution

It introduces a complete transport framework for describing heavy-flavour production and explores medium effects in small collision systems.

Findings

Heavy quarks can approach kinetic equilibrium with the medium.

Recombination with thermal partons influences heavy-flavour hadron flow.

Medium effects may be present even in small collision systems.

Abstract

The peculiar role of heavy-flavour observables in relativistic heavy-ion collisions is discussed. Produced in the early stage, $c$ and $b$ quarks cross the hot medium arising from the collision, interacting strongly with the latter, until they hadronize. Depending on the strength of the interaction heavy quarks may or not approach kinetic equilibrium with the plasma, tending in the first case to follow the collective flow of the expanding fireball. The presence of a hot deconfined medium may also affect heavy-quark hadronization, being possible for them to recombine with the surrounding light thermal partons, so that the final heavy-flavour hadrons inherit part of the flow of the medium. Here we show how it is possible to develop a complete transport setup allowing one to describe heavy-flavour production in high-energy nuclear collisions, displaying some major results one can obtain. Finally, the possibility that the formation of a hot deconfined medium even in small systems (high-multiplicity p-Au and d-Au collisions, so far) may affect also heavy-flavour observables is investigated.