Eur. Phys. J. A 11, 319-327 (2001)
Chiral quark model with infrared cut-off for the description of meson properties in hot matter
D.B. Blaschke1, 2, G.R.G. Burau1, M.K. Volkov2 and V.L. Yudichev21 Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
2 Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russian Federation
david@darss.mpg.uni-rostock.de
(Received: 11 July 2001 Communicated by V.V. Anisovich)
Abstract
A simple chiral quark model of the Nambu-Jona-Lasinio (NJL) type with a
quark confinement mechanism is constructed for the description of the
light-meson sector of QCD at finite temperature.
Unphysical quark production thresholds in the NJL model are excluded by an
infrared cut-off in the momentum integration within quark loop diagrams.
This chiral quark model satisfies the low-energy theorems.
Using the vacuum masses and decay widths of - and
-mesons
for fixing the model parameters, the properties of the
-meson
are derived.
Within the Matsubara formalism, the model is systematically extended to
finite temperatures where chiral symmetry restoration due to a dropping
constituent quark mass entails a vanishing of the infrared cut-off
(deconfinement) at the pion Mott temperature
MeV.
Besides the pion mass and weak decay constant, the masses, coupling
constants and decay widths of
- and
-mesons in hot matter
are investigated.
The quark-antiquark decay channel of the light mesons is opened for
only and becomes particularly strong for the
-meson.
The two-pion decay channel below
has almost constant width for the
-meson up to
, but for the
-meson it closes below
such that a scalar meson state with vanishing width is obtained as a precursor
of the chiral/deconfinement transition.
11.30.Rd - Chiral symmetries.
12.38.Lg - Other nonperturbative calculations.
13.25.-k - Hadronic decays of mesons.
11.10.Wx - Finite-temperature field theory.
© Società Italiana di Fisica, Springer-Verlag 2001