CHIRAL SYMMETRY AMPLITUDES IN THE S-WAVE ISOSCALAR AND ISOVECTOR CHANNELS AND THE SIGMA, F(0)(980), A(0)(980) SCALAR MESONS

摘要

We use a non-perturbative approach which combines coupled channel Lippmann-Schwinger equations with meson-meson potentials provided by the lowest order chiral Lagrangian. By means of one parameter, a cut off in the momentum of the loop integrals, which results of the order of 1 GeV, we obtain singularities in the S-wave amplitudes corresponding to the sigma, f(0) and ail resonances, The phi pi --> pi pi,pi pi --> phase shifts and inelasticities in the T = 0 scalar channel are well reproduced as well as the pi(0) eta and mass distributions in the T = 1 channel. Furthermore, the total and partial strong decay widths of the f(0) and a(0) resonances are properly reproduced. The results seem to indicate that chiral symmetry constraints at low energy and unitarity in coupled channels is the basic information contained in the meson-meson interaction below root s similar or equal to 1.2 GeV. (C) 1997 Elsevier Science B.V. [References: 59]