Study of Heavy Hadron Production in Au + Au Collisions at a Center-of-Mass Energy of $\sqrt{s_{NN}}=200$ GeV

Abstract

Using the Monte Carlo HYDJET++ model, the transverse momentum ($p_{T}$) spectra of heavy hadrons ($D^{0}$, $\overline{D}^{0}$, $D^{+}$, $D^{-}$ and $\Lambda_{c}$), as well as the nuclear modification factors of $D^{0}$ and $D^{\pm}$, produced in Au + Au collisions at $\sqrt{s_{NN}} = 200$ GeV RHIC energy across various centrality bins, are presented. This study is motivated by the need to understand the centrality dependence of the charm enhancement factor ($\gamma_{c}$) and the roles of different hadronization mechanisms such as coalescence and fragmentation, in charm hadron production. To achieve the best description of heavy hadron production, several input parameters in both the soft and hard components of the model are tuned. The study finds a decreasing trend of $\gamma_{c}$ from central to peripheral collisions and a mass dependence across charm hadrons. Moreover, the model effectively reproduces experimental data of $p_{T}$ spectra at low and intermediate $p_{T}$, capturing key features of charm hadron production in the quark-gluon plasma medium. However, it overpredicts the data at high $p_{T}$, indicating the need for improvements in modeling heavy quark energy loss mechanisms. Further, the nuclear modification factors ($R_{AA}$ and $R_{CP}$) for $D^{0}$ mesons exhibit significant suppression in central collisions, which matches with experimental observations. This highlights the roles of collisional and radiative energy loss due to collective effects, such as coalescence and radial flow. The antiparticle-to-particle and mixed particle ratios are also presented, showing good agreement with experimental data and revealing limitations in baryon production due to the absence of heavy quark coalescence in HYDJET++.