Scalar mesons nonet in a scaled effective Lagrangian

A scaled SU(3) Nambu - Jona-Lasinio Lagrangian is used to compute the mass of the nine scalar mesons in the vacuum and the mass of the gluball. It is shown that a suitable choice of the vacuum gluon condensate allows to reproduce the experimental masses of the scalar mesons except for the {$K^*_{0}$}(1430). This choice corresponds to a weak coupling between the gluon and quark condensates, giving a {$f_{0}$}(1500) or a {$f_{J}$}(1710) which is nearly a pure glueball.Comment: 12 pages, Latex, use elsart.st

Phase transition and thermodynamics of a hot and dense system in a scaled NJL model

The chiral phase transition of a hot and dense system of quarks is studied within a modified SU(3) NJL lagrangian that implements the QCD scale anomaly. The u- and s-quark condensates can feel or not the same chiral restoration depending on the considered region of the 3-dimension space T_c(\mu_uc,\mu_sc). The temperature behaviour of the pressure and of the energy and entropy densities of the u- and s-quark system is investigated. At high temperature, the non-vanishing bare s-quark mass only modifies slightly the usual behaviour associated with an ideal quark gas.Comment: 23 pages, LaTeX, uses elsart.sty. This version of the paper includes the figures (ps

A General Approach of Quasi-Exactly Solvable Schroedinger Equations with Three Known Eigenstates

We propose a general method for constructing quasi-exactly solvable potentials with three analytic eigenstates. These potentials can be real or complex functions but the spectrum is real. A comparison with other methods is also performed