Production of open-charm mesons in relativistic heavy-ion collisions

TL;DR

This paper develops a theoretical model for open charm meson production in relativistic heavy-ion collisions, fitting lattice QCD data to explore charm quark interactions with the quark-gluon plasma and comparing model predictions with experimental results.

Contribution

It introduces two models for the charm quark diffusion coefficient based on lattice QCD fits, highlighting the importance of temperature and momentum dependence for describing D-meson observables.

Findings

Model-A fits the nuclear modification factor R_AA at RHIC and LHC.

Model-B better describes the elliptic flow v_2 at moderate p_T.

Broadening of azimuthal correlations is more pronounced in Model-B.

Abstract

We present a theoretical framework to study open charm production in relativistic heavy-ion collisions. The coupling strength between the charm quarks and the QGP constituents, quantified by the spatial diffusion coefficient $2\pi TD_{s}$, is obtained by performing a phenomenological fit analysis to the lattice QCD calculations, resulting in $2\pi TD_{s}=const.$ (\textbf{Model-A}) and $2\pi TD_{s}=1.3 + (T/T_{c})^2$ (\textbf{Model-B}). We find that the relative azimuthal distribution of the initially back-to-back generated $c\bar{c}$ pairs presents a broadening behaviour, which is more pronounced for $c\bar{c}$ pairs with small initial $p_{\rm T}$, and when the Model-B approach is adopted. The competition between the initial drag and the subsequent collective effects tends to restrict the time dependence of charm quark $R_{\rm AA}$. Concerning the theoretical uncertainty on final D-meson nuclear modification, the nuclear shadowing and pp baseline components are dominat at high and low $p_{\rm T}$ ($p_{\rm T}\lesssim3~{\rm GeV/{\it c}}$), respectively. The measured D-meson $R_{\rm AA}(p_{\rm T})$ favors Model-A assumption for the diffusion coefficient both at RHIC and LHC, while their $v_{2}(p_{\rm T})$ prefer Model-B at moderate $p_{\rm T}$. These results confirm the necessity to consider the temperature- and/or momentum-dependence of $2\pi TD_{s}$ to describe well the D-meson $R_{\rm AA}$ and $v_{\rm 2}$ simultaneously.