Bochum 2009 – scientific programme

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HK: Fachverband Hadronen und Kerne

HK 12: Heavy Ion Collisions and QCD phases

HK 12.2: Group Report

Monday, March 16, 2009, 17:00–17:30, H-ZO 10

Phases of QCD, role of strangeness and PNJL model with 2+1 flavors — •Thomas Hell, Nino Bratovic, Marco Cristoforetti, Simon Rößner, and Wolfram Weise — Physik-Department, Technische Universität München, D-85747 Garching, Germany

We investigate the QCD phase diagram within a three-flavor Nambu and Jona-Lasinio (NJL) model including the Polyakov loop as an order parameter for the confinement-deconfinement transition. Of particular interest is the impact of diquark condensation and color superconducting phases in the high-density region.

Furthermore, we present a nonlocal covariant extension [1] of the three-flavor NJL model, with built-in constraints from the running coupling of QCD at high-momentum and instanton physics at low-momentum scales. The momentum-dependent dynamical quark mass derived from this approach is in agreement with results from Dyson-Schwinger equations and lattice QCD. At finite temperature, the inclusion of the Polyakov loop and its gauge invariant coupling to quarks reproduces the dynamical entanglement of the chiral and deconfinement crossover transitions as in the (local) PNJL model, but now without the requirement of introducing an artificial momentum cutoff. Steps beyond the mean-field approximation are made including mesonic correlations through quark-antiquark ring summations.

[1] T. Hell et al., arXiv:0810.1099, Phys. Rev. D (2008), in print.

Work supported by BMBF, GSI, the DFG Excellence Cluster “Origin and Structure of the Universe” and by the Elitenetzwerk Bayern.