Marlene Nahrgang

Freeze-out conditions from net-proton and net-charge fluctuations at RHIC

Abstract We calculate ratios of higher-order susceptibilities quantifying fluctuations in the number of net-protons and in the net-electric charge using the Hadron Resonance Gas (HRG) model. We take into account the effect of resonance decays, the kinematic acceptance cuts in rapidity, pseudo-rapidity and transverse momentum used in the experimental analysis, as well as a randomization of the isospin of nucleons in the hadronic phase. By comparing these results to the latest experimental data from the STAR Collaboration, we determine the freeze-out conditions from net-electric charge and net-proton distributions and discuss their consistency.

Influence of hadronic bound states above

We investigate how the possible existence of hadronic bound states above the deconfinement transition temperature

T_c

{T}_{c}

on heavy-quark observables in Pb + Pb collisions at at the CERN Large Hadron Collider

affects heavy-quark observables, such as the nuclear modification factor, the elliptic flow, and azimuthal correlations. Lattice QCD calculations suggest that above

Azimuthal correlations of heavy quarks in Pb + Pb collisions at

{T}_{c}

\sqrt{s}=2.76

the effective degrees of freedom might not be exclusively partonic but that a certain fraction of hadronic degrees of freedom might already form at higher temperatures. This is an interesting question by itself but also has a strong influence on other probes of the strongly interacting matter produced in ultrarelativistic heavy-ion collisions. A substantial fraction of hadronic bound states above

TeV at the CERN Large Hadron Collider

{T}_{c}

Elliptic and triangular flow of heavy flavor in heavy-ion collisions

reduces on average the interaction of the heavy quarks with colored constituents of the medium. We find that all studied observables are highly sensitive to the active degrees of freedom in the quark-gluon plasma.

Chiral fluid dynamics with explicit propagation of the Polyakov loop

In this paper we study the azimuthal correlations of heavy quarks in Pb+Pb collisions with √ s = 2.76 TeV at LHC. Due to the interaction with the medium heavy quarks and antiquarks are deflected from their original direction and the initial correlation of the pair is broadened. We investigate this effect for different transverse momentum classes. Low-momentum heavy-quark pairs lose their leading order back-to-back initial correlation, while a significant residual correlation survives at large momenta. Due to the larger acquired average deflection from their original directions the azimuthal correlations of heavy-quark pairs are broadened more efficiently in a purely collisional energy loss mechanism compared to including radiative corrections. This discriminatory feature survives when next-to-leading order production processes are included.

Impact of resonance regeneration and decay on the net proton fluctuations in a hadron resonance gas

We investigate the elliptic and the triangular flow of heavy mesons in ultrarelativistic heavy-ion collisions at RHIC and the LHC. The dynamics of heavy quarks is coupled to the locally thermalized and fluid dynamically evolving quark-gluon plasma. The elliptic flow of