Kaon semileptonic decay (K_{l3}) form factor in the nonlocal chiral quark model

TL;DR

This paper calculates kaon semileptonic decay form factors using a nonlocal chiral quark model from the instanton vacuum, emphasizing flavor SU(3) symmetry breaking effects and matching experimental data.

Contribution

It provides parameter-free theoretical predictions of K_{l3} form factors that satisfy key low-energy theorems and highlight the importance of SU(3) symmetry breaking.

Findings

Results agree well with experimental data.

Flavor SU(3) symmetry breaking is crucial for accurate form factors.

The model satisfies the Callan-Treiman and Ademollo-Gatto theorems.

Abstract

We investigate the kaon semileptonic decay (K_{l3}) form factors within the framework of the nonlocal chiral quark model from the instanton vacuum, taking into account the effects of flavor SU(3) symmetry breaking. All theoretical calculations are carried out without any adjustable parameter. We also show that the present results satisfy the Callan-Treiman low-energy theorem as well as the Ademollo-Gatto theorem. It turns out that the effects of flavor SU(3) symmetry breaking are essential in reproducing the kaon semileptonic form factors. The present results are in a good agreement with experiments, and are compatible with other model calculations.