Open charm physics with Heavy Ions: theoretical overview

TL;DR

This paper reviews the role of heavy-flavour observables in relativistic heavy-ion collisions, discussing their interactions with the hot medium, hadronization processes, and how transport models and lattice-QCD insights enhance understanding of open charm physics.

Contribution

It presents a comprehensive transport framework for heavy-flavour production in high-energy nuclear collisions, integrating recent lattice-QCD results and exploring effects in small systems.

Findings

Heavy quarks can approach kinetic equilibrium with the plasma depending on interaction strength.

Recombination with thermal partons influences the flow of final heavy-flavour hadrons.

A complete transport setup can describe heavy-flavour production and medium effects in nuclear collisions.

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. Information coming from recent lattice-QCD simulations concerning both the heavy-flavour transport coefficients in the hot QCD plasma and the nature of the charmed degrees around the deconfinement transition is also presented. 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.