Abstract:
To describe the latest experimental situation on the Kl3 decays (which shows large λ+≈0.07 along with a ξ≈-0.9), effective-dipole form-factors, satisfying exact results of first order breaking of the chiral SU3 ⊗ SU3 symmetry down to SU2, are proposed. To the same order in the symmetry breaking the relation, F+(t) + tF-(t) (m2K - m2π) = F+(0), holds for a wide enough range of t, so that soft-meson current-algebra constraints are automatically satisfied to that order. © 1971.