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HK: Hadronen und Kerne

HK 66: Struktur von Baryonen und Mesonen VII

HK 66.5: Talk

Thursday, March 27, 1997, 18:00–18:15, HS I

A linear σ -model with quark confinement — •Christiane Kettner, Kurt Langfeld, and Hugo Reinhardt — Institut für Theoretische Physik, Univ. Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen

The field strength approach to Yang–Mills theories reveals a NJL–type quark interaction with repulsive channels at strong coupling [1]. Here we propose an extended linear σ –model which mimics this feature. Similar as in [2] also coloured mesonic degrees of freedom are admitted, which transform under the adjoint representation of a SU(2) colour group. It is shown that these fields can aquire a non–vanishing VEV with the vacuum being in a Kosterlitz–Thouless phase. Then quark confinement is realized in the sense that unphysical quark thresholds are absent in mesonic correlation functions. It turns out that the repulsive channels are essential to avoid tachyonic meson modes. We present results for pion physics and phase transitions at finite densities and temperatures.

Supported in part by DFG under contract Re 856/1-3 and by Graduiertenkolleg ”Hadronen und Kerne”.

[1] K. Langfeld, M. Schaden, Phys. Lett. B272 (1991) 100; K. Langfeld, [1]   R. Alkofer, H. Reinhardt, Phys. Lett. B277 (1992) 163.

[2] K. Langfeld, M. Rho, Nucl. Phys. A596 (1996) 451.