Scattering phases in the broken phase of the 4-d O(4) non-linear sigma-model

TL;DR

This study uses lattice Monte Carlo simulations to measure scattering phases in the broken phase of the 4D O(4) sigma-model, identifying the sigma-resonance and confirming results align with perturbative predictions.

Contribution

It provides the first non-perturbative determination of scattering phases and resonance parameters in the 4D O(4) sigma-model using Luescher's method.

Findings

Observation of the sigma-resonance in the isospin-0 channel

Extraction of the sigma mass and width from lattice data

Results consistent with perturbative calculations

Abstract

Using Luescher's method we determine the elastic scattering phases in the broken phase of the 4-dimensional O(4) non-linear sigma-model from the two-particle energy spectrum in a Monte-Carlo study on finite lattices. In the isospin-0-channel we observe the sigma-resonance and extract its mass and its width. In all scattering channels investigated the results are consistent with perturbative calculations.