The data on the form factors of the $K_{ e4}$ decay permit to fix a value of the non-specified in the theory parameter entering in the lagrangian of the system of $0^+$ and $0^-$ mesons . Then, for a mass of the lightest $\sigma$-meson we find: $m_{ \sigma}$=663 MeV. As for a nature of the spin-1 mesons, also contributing into $K_{ e4}$ form factors, the data do not allow to interpret them as the gauge bosons of the chiral theory.
Categories: hep-ph