In memory of Paco Yndurain: A precise determination of pion-pion scattering from experiment and dispersion relations

TL;DR

This paper presents a precise determination of pion-pion scattering amplitudes using experimental data and dispersion relations, notably improving accuracy in the intermediate energy region through advanced Roy Equation techniques.

Contribution

It introduces a refined method employing once-subtracted Roy Equations, enhancing the precision of pion-pion scattering amplitude analysis over previous approaches.

Findings

Improved precision in pion-pion scattering amplitude determination.

Effective use of once-subtracted Roy Equations for better accuracy.

Enhanced understanding of scattering processes in the intermediate energy range.

Abstract

This talk is dedicated to the memory of Paco Yndurain, the original speaker in the conference. After a short account of his scientific career, we briefly review our ongoing collaboration to determine precisely the $\pi\pi$ scattering amplitude including the most recent data by means of Forward Dispersion Relations and Roy Equations. A remarkable improvement in precision over the intermediate energy region is obtained by using once-subtracted Roy Equations in addition to the standard twice-subtracted ones.