Heidelberg 2015 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 44: Heavy Ion Collisions and QCD Phases 5

HK 44.2: Talk

Wednesday, March 25, 2015, 15:00–15:15, T/HS1

The Chiral Phase Transition in the Presence of Vector Mesons from the Functional Renormalization Group Approach. — •Jürgen Eser, Mara Grahl, and Dirk Rischke — Institut für Theoretische Physik, Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main

The characteristics of the transition in quantum chromodynamics (QCD) from familiar hadronic matter to the quark-gluon plasma (QGP) are subject to an ongoing debate. This transition is associated with the spontaneous restoration of chiral symmetry. Experimental setups such as CBM at GSI aim to produce the QGP state via heavy-ion collisions. Here, dropping in-medium masses of (axial-)vector mesons are promising candidates for indicating the restoration of chiral symmetry. Furthermore, (axial-)vector mesons play an important role in QCD phenomenology due to vector meson dominance. It is therefore crucial to include those degrees of freedom in a theoretical analysis. Nonperturbative methods, such as the functional renormalization group (FRG), provide new insights into the QCD transition as they do not rely on weak couplings and avoid essential drawbacks of the lattice approach.

We shed light on the two-flavor chiral phase transition in the presence of (axial-)vector mesons by applying the FRG formalism to an effective model for QCD. The order of the phase transition within this extended linear sigma model is determined. Moreover, we investigate the mass degeneracy of chiral partners occuring at the phase boundary.