  In a long distance Lagrangian approach to the low lying meson phenomenology
we present and discuss the most general spin zero multi-quark interaction
vertices of non-derivative type which include a set of effective interactions
proportional to the current quark masses, breaking explicitely the chiral
SU(3)_L X SU(3)_R and U_A(1) symmetries. These vertices are of the sameorder in
Nc counting as the 't Hooft flavor determinant interaction and the 8 quark
interactions which extend the original leading in Nc four quark interaction
Lagrangian of Nambu and Jona-Lasinio. The Nc assignements match the counting
rules based on arguments set by the scale of spontaneous chiral symmetry
breaking. With path integral bosonization techniques which take appropriately
into account the quark mass differences we derive the mesonic Lagrangian up to
3-point mesonic vertices. We demonstrate that explicit symmetry breaking
effects in interactions are essential to obtain the correct empirical ordering
and magnitude of the splitting of certain states such as m_K < m_eta for the
pseudoscalars and m{kappa(800)} < m{a0(980)} m{f0(980)} in the scalar sector,
and achieve total agreement with the empirical low lying meson mass spectra.
With all parameters of the model fixed by the spectra we analyze further a bulk
of two body decays at tree level of the bosonic Lagrangian: the strong decays
of the scalars sigma->pi pi, f0->pi pi, kappa->pi K, a0(980)->pi eta, as well
as the two photon decays of a0, f0 and sigma mesons and the anomalous decays of
the pseudoscalars {pi,eta,eta'}-> 2 photons. Our results for the strong decays
are within the current expectations and the pseudoscalar radiative decays are
in very good agreement with data. The radiative decays of the scalars are
smaller than the observed values for the f0 and the sigma, but reasonable for
the a0. A detailed discussion accompanies all the results.
