Charmed hadron chemistry and flow in heavy and light ion collisions at the LHC

Abstract

We study the charmed meson and baryon production and elliptic flow in ultra-relativistic nucleus-nucleus collisions at the LHC energies. The space-time evolution of quark-gluon plasma (QGP) produced in these energetic collisions is obtained via the (3+1)-dimensional CLVisc hydrodynamics model, the heavy quark dynamics inside the QGP is simulated using an improved Langevin model that incorporates both elastic and inelastic parton energy loss processes, and the heavy quark hadronization is simulated utilizing a comprehensive coalescence-fragmentation model. Using our combined approach, we first calculate charmed hadron ratios, $\Lambda_c/D^0$ and $D_s/D^0$, as well as their elliptic flow ($v_2$) as a function of transverse momentum ($p_T$) for different centralities in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$~TeV. Due to strangeness enhancement and parton coalescence effects, $D_s/D^0$ and $\Lambda_c/D^0$ ratios increase from peripheral to central collisions, and such centrality dependence for $\Lambda_c/D^0$ is stronger than $D_s/D^0$. We further predict the $p_T$ and centrality dependences of charmed hadron chemistry and $v_2$ in smaller Xe+Xe, Ar+Ar and O+O collisions at the LHC energies. Strong centrality and system size dependences for $\Lambda_c/D^0$ and $D_s/D^0$ ratios are observed across four collision systems. As for charmed hadron flow, both system size and collision geometry are important to understand the centrality dependence of $v_2$ in different collision systems. Our study provides a significant reference for studying heavy quark evolution and hadronizaiton in large and small systems in relativistic nuclear collisions.