Tamás Herpay (Budapest):
Mapping the boundary of the first order finite temperature restoration of chiral symmetry in the m_{π}m_{K} plane with a linear sigma model
Abstract:
The phase diagram of the threeflavor QCD is mapped out in the low mass corner of the
(m_{π}m_{K})plane with help of the SU_{L}(3)×SU_{R}(3) linear sigma model.
A novel zero temperature parametrization is proposed for the mass dependence of the couplings away from
the physical point based on the three flavor chiral perturbation theory. Oneloop thermodynamics is
constructed by applying optimized perturbation theory. The unknown dependence of the scalar spectra
on the pseudoscalar masses limits the accuracy of the predictions. Results are compared to lattice
data and similar investigations with other variants of effective chiral models. The critical value
of the pion mass is below 65 MeV for all mK values <~800 MeV. Along the diagonal m_{π}=m_{K}, we
estimate m_{crit}(diag)=40±20 MeV.
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