Analysis of tau -> Ks pion nu_tau Belle data in a chiral framework

TL;DR

This paper provides a theoretical analysis of the tau -> Ks pion nu_tau decay spectrum using resonance chiral theory, constrained by dispersion relations and QCD, to accurately model form factors and extract resonance parameters.

Contribution

It introduces a novel approach combining resonance chiral theory with dispersion relations to describe tau decay form factors and determine resonance parameters.

Findings

Good fit to Belle data achieved

Determination of K*(892) resonance parameters

Low-energy form factor parameterization obtained

Abstract

The recent measurement of the tau -> Ks pion nu_tau spectrum by the Belle Collaboration provides the frame to set forth a theoretical description of the decay, which is based on the contributing vector F_+(s) and scalar F_0(s) form factors. We show that a good representation of data is obtained through the use of form factors calculated within resonance chiral theory and constrained by dispersion relations and short-distance QCD. Hence we obtain a determination of K*(892) parameters and the low-energy parameterization of F_+(s).