# A Virtual Tribute to Quark Confinement and the Hadron Spectrum 2021

Aug 2 – 6, 2021
online
Europe/Brussels timezone

## Dispersive study of $K\pi$ scattering and determination of threshold parameters and of $\kappa/K_0^*(700)$ resonance properties

Aug 5, 2021, 10:50 AM
20m
online

#### online

Parallel contribution B: Light quarks

### Speaker

Jose R. Pelaez Sagredo (Universidad Complutense)

### Description

We have recently completed the coupled dispersive analysis of $\pi K$ pi pi -> K anti-K data.
We show that just fitting data fails to satisfy the dispersive representation and leads to inconsistencies with threshold sum-rules as well as unreliable resonance parameterizations.

Our main result is a set of constrained fits to data that satisfy 16 dispersion relations of different kinds and allow for a reliable extraction of threshold and subtreshold parameters to be compared with Chiral Perturbation Theory and lattice QCD. In addition, we obtain a precise dispersive determination of the controversial light kappa-meson parameters, which has therefore become a "confirmed" state in the PDG, completing the light meson scalar nonet. The constrained fits to data are easy to implement and ready for further theoretical and experimental studies.

### Primary authors

Jose R. Pelaez Sagredo (Universidad Complutense) Dr Arkaitz Rodas (College of William and Mary)