Effects of Heavy Quark Energy Loss and Coalescence on the Suppression and Flow of Heavy Mesons, Baryons, and Jets

In order to model heavy quarks traversing the quark gluon plasma created in heavy ion collisions, several physical effects must be taken into account. After heavy quarks are created in hard scatterings at $t=0$ in heavy ion collisions at RHIC and the LHC, they traverse the strongly coupled QGP medium, losing energy to it, undergo Brownian-like motion due to the thermal properties of the medium and finally hadronize with either particles from the medium, or other hard partons from hard scatterings. We introduce heavy quarks in the Hybrid Model, and implement each of these three effects. To model strongly coupled energy loss of a heavy quark that starts out ultrarelativistic, loses energy, slows down, becomes non-relativistic at later times, and ultimately comes to rest we turn to AdS/CFT. To date, holographic calculations have provided separate descriptions for the rates of energy loss $dE/dx$ either for ultrarelativistic massless quarks and gluons or for infinitely massive quarks in strongly coupled plasma, with the latter calculation valid for $\sqrt{\gamma}<M/(\sqrt{\lambda}T}$, where $\gamma$ is the Lorentz boost factor for a heavy quark with velocity $v$ and mass $M$ moving through strongly coupled plasma with 't Hooft coupling $\lambda$ and temperature $T$. We provide an ansatz for uniquely incorporating both regimes to give a unified but approximate description of how a heavy quark that is initially ultrarelativistic loses energy all the way until it comes to rest. We also implement Gaussian momentum broadening to model the Brownian motion of the quark, ensuring that the heavy quarks can thermalize at late times. To model the hadronization of heavy quarks that hadronize by combining with soft medium partons we implement a local color neutralization model for recombination, and to model the hadronization of heavy quarks that hadronize with other hard shower partons we implement Lund string hadronization using PYTHIA. We introduce criteria for deciding which heavy quarks to hadronize in each way. We confront our predictions for the suppression $R_{AA}$ and azimuthal anisotropies $v_2$ of B- and D-mesons and $\Lambda_c$ baryons, $R_{AA}$ of B-tagged jets, as well as baryon-to-meson ratios, with available experimental data from ALICE, ATLAS and CMS.