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.
@article{arxiv.hep-lat/9312040,
title = {Scattering phases in the broken phase of the 4-d O(4) non-linear sigma-model},
author = {J. Westphalen and F. Zimmermann and M. Goeckeler and H. A. Kastrup},
journal= {arXiv preprint arXiv:hep-lat/9312040},
year = {2009}
}