Sigma pole position and errors of a once and twice subtracted dispersive analysis of pi-pi scattering data

TL;DR

This paper uses new kaon decay data and dispersion relations to precisely determine the sigma meson pole position, comparing uncertainties from different Roy's equation subtractions.

Contribution

It introduces a detailed dispersive analysis combining new data and sum rules to accurately locate the sigma meson pole, including uncertainty assessment.

Findings

Precise sigma pole position obtained

Comparison of once- and twice-subtracted Roy's equations

Uncertainty sources analyzed

Abstract

We show how the new precise data on kaon decays together with forward dispersion relations, sum rules and once- and twice-subtracted Roy's equations allow for a precise determination of the sigma meson pole position. We present a comparison and a study of the different sources of uncertainties when using either once- or twice-subtracted Roy's equations to analyze the data. Finally we present a preliminary determination of the sigma pole from the constrained dispersive data analysis.