Bochum 2009 – scientific programme

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HK: Fachverband Hadronen und Kerne

HK 79: Heavy Ion Collisions and QCD phases

HK 79.5: Talk

Friday, March 20, 2009, 12:30–12:45, H-ZO 10

Flavour off diagonal susceptibilties in the PNJL model — •Simon Rößner, Thomas Hell, Nino Bratovic, and Wolfram Weise — Physik Department, TU München, 85748 Garching, Germany

We present an investigation of flavour sensitive quark number susceptibilities based on the 2-flavour Polyakov loop extended Nambu and Jona-Lasinio (PNJL) model [1]. This calculation features the two most important non-perturbative effects of QCD at temperatures below the 1 GeV-scale, spontaneous chiral symmetry breaking and confinement. The astonishingly good agreement of the equation of state with full lattice QCD calculations [2] persists for finite isovector chemical potentials. As a central result, finite up-down quark number susceptibilities are found even in the absence of explicit colour and flavour mixing terms in the model Lagrangian.

The PNJL model study suggests that the up-down quark number susceptibilities are intertwined with the Polyakov loop degrees of freedom. This observation can be understood with a simple model which features a coupling of both up and down quark densities to a flavour-blind degree of freedom. It remains an open issue, however, to what extend the modelled mechanism is at work in full QCD.

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

[1] S. Rößner, T. Hell, C. Ratti, and W. Weise, Nucl. Phys. A814, 118 (2008).

[2] S. Rößner, C. Ratti, and W. Weise, Phys. Rev. D75, 034007 (2007).