What The $K_{E4}$ Decay Tells Us On A Value Of $\Sigma$-Particle Mass And On A Nature Of The Spin-1 Mesons

TL;DR

This paper uses $K_{e4}$ decay data to determine the $\sigma$-meson mass and to analyze the nature of spin-1 mesons, concluding they are not gauge bosons of chiral theory.

Contribution

It provides a new estimate of the $\sigma$-meson mass and clarifies the non-gauge boson nature of spin-1 mesons based on $K_{e4}$ decay form factors.

Findings

$\sigma$-meson mass estimated at 663 MeV

Spin-1 mesons are not gauge bosons of chiral theory

$K_{e4}$ decay data constrains meson properties

Abstract

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.