Scalar mesons moving in a finite volume and the role of partial wave mixing

TL;DR

This paper presents a method to extract phase shifts and resonance parameters from finite-volume lattice spectra involving moving particles, accounting for partial wave mixing to improve the accuracy of scattering studies.

Contribution

A simple derivation of the finite-volume method for moving particles, including partial wave mixing corrections, applied to pi pi and pi K scattering to enhance lattice simulation analysis.

Findings

Effective extraction of resonance parameters from multiple total momenta.

Inclusion of partial wave mixing corrections improves accuracy.

Application to pi pi and pi K scattering demonstrates method viability.

Abstract

Phase shifts and resonance parameters can be obtained from finite-volume lattice spectra for interacting pairs of particles, moving with nonzero total momentum. We present a simple derivation of the method that is subsequently applied to obtain the pi pi and pi K phase shifts in the sectors with total isospin I=0 and I=1/2, respectively. Considering different total momenta, one obtains extra data points for a given volume that allow for a very efficient extraction of the resonance parameters in the infinite-volume limit. Corrections due to the mixing of partial waves are provided. We expect that our results will help to optimize the strategies in lattice simulations, which aim at an accurate determination of the scattering and resonance properties.