Heavy-Quark Probes of the Quark-Gluon Plasma at RHIC

We present a study of the heavy-flavor dynamics in nucleus-nucleus collisions. The initial (hard) production of c and b quarks is taken from NLO pQCD predictions. The presence of a hot medium (a Quark Gluon Plasma described by hydrodynamics) affects the final spectra of open-charm (beauty) hadrons and their decay electrons with respect to what found in pp collisions. The propagation of c and b quarks in the plasma is based on a picture of multiple uncorrelated random collisio...

We calculate diffusion and hadronization of heavy quarks in high-energy heavy-ion collisions implementing the notion of a strongly coupled quark-gluon plasma in both micro- and macroscopic components. The diffusion process is simulated using relativistic Fokker-Planck dynamics for elastic scattering in a hydrodynamic background. The heavy-quark transport coefficients in the medium are obtained from non-perturbative $T$-matrix interactions which build up resonant correlations ...

The relativistic diffusion process of heavy quarks is formulated on the basis of the relativistic Langevin equation in It\^{o} discretization scheme. The drag force inside the quark-gluon plasma (QGP) is parametrized according to the formula for the strongly coupled plasma obtained by the AdS/CFT correspondence. The diffusion dynamics of charm and bottom quarks in QGP is described by combining the Langevin simulation under the background matter described by the relativistic h...

We revisit the question of the measured, unexpectedly large, heavy flavor suppression, $R_{AA}(p_T) \ll 1$, in nucleus-nucleus collisions at RHIC and compare two new theoretical approaches to the $D$- and $B$-meson quenching. In the first model, radiative energy loss, collisional energy loss and heavy quark-resonance interactions are combined to evaluate the drag and diffusion coefficients in the quark-gluon plasma and the mixed phase. These are applied in a relativistic Fokk...

In relativistic heavy ion collisions at RHIC and the LHC, a quark gluon plasma (QGP) is created for a short duration of about 10fm/c. Quarkonia (bound states of $c\bar{c}$ and $b\bar{b}$) are sensitive probes of this phase on length scales comparable to the size of the bound states which are less than 1fm. Observations of quarkonia in these collisions provide us with a lot of information about how the presence of a QGP affects various quarkonium states. This has motivated the...

The diffusion of heavy quarks through the quark-gluon plasma (QGP) as produced in high-energy heavy-ion collisions has long been recognized as an excellent probe of its transport properties. In addition, the experimentally observed heavy-flavor hadrons carry valuable information about the hadronization process of the transported quarks. Here we review recent progress in the theoretical developments of heavy-quark interactions in the QGP and how they relate to the nonperturbat...

We study the dynamics of open charm production and the dilepton radiation of the semi-leptonic decays of correlated $D\bar D$ pairs versus the quark-gluon plasma (QGP) radiation and hadronic sources in relativistic heavy-ion collisions. Our study is based on the Parton-Hadron-String Dynamics (PHSD) transport approach employing a non-perturbative QCD description of the strongly interacting quark-gluon plasma (sQGP) in terms of dynamical quasiparticles and the EoS based on latt...

A long standing question in the field of heavy-ion collisions is whether charm quarks are thermalized within the Quark Gluon Plasma. In recent years, progress in lattice QCD simulations has led to reliable results for the equation of state of a system of 2+1 flavors (up, down, and strange) and 2+1+1 flavors (up, down, strange, and charm). We find that the equation of state strongly affects differential flow harmonics and a preference is seen for thermalized charm quarks at th...

The rapid thermalization of quarks and gluons in the initial stages of relativistic heavy-ion collisions is treated using analytic solutions of a nonlinear diffusion equation with schematic initial conditions, and for gluons with boundary conditions at the singularity. On a similarly short time scale of $t \le1$ fm/$c$, the stopping of baryons is accounted for through a QCD-inspired approach based on the parton distribution functions of valence quarks, and gluons. Charged-had...

We study quantitatively the formation and evolution of B_c bound states in a space-time domain of deconfined quarks and gluons (quark-gluon plasma, QGP). At the Relativistic Heavy Ion Collider (RHIC) one expects for the first time that typical central collisions will result in multiple pairs of heavy (in this case charmed) quarks. This provides a new mechanism for the formation of heavy quarkonia which depends on the properties of the deconfined region. We find typical enhanc...