K-pi interaction in finite volume and the K* resonance

TL;DR

This paper uses chiral unitary theory to analyze K-pi interactions in finite volume, extracting phase shifts, K* resonance properties, and comparing with lattice QCD and Luscher methods.

Contribution

It introduces a novel approach to determine K* resonance parameters from finite-volume energy levels using chiral unitary theory, with comparisons to existing methods.

Findings

K* mass and decay width dependence on pion mass

Agreement with lattice QCD results

Validation of the method against Luscher approach

Abstract

We evaluate energy levels of the K-pi system in the K* channel in finite volume using chiral unitary theory. We use these energy levels to obtain K-pi phase shifts, and then obtain the K* mass and its decay width. We investigate their dependence on the pion mass and compare this with Lattice QCD calculations. We also compare our method with the standard Luscher approach, and solve the inverse problem to obtain the K-pi phase shifts from these "synthetic" lattice data.