The isospin-2 pi pi system provides a useful testing ground for determining elastic hadron scattering parameters from finite-volume spectra obtained using lattice QCD computations. A reliable determination of the excited state spectrum of two pions in a cubic box follows from variational analysis of correlator matrices constructed using a large basis of operators. A general operator construction is presented which respects the symmetries of a multi-hadron system in flight. This is applied to the case of pi pi and allows for the determination of the scattering phase-shifts at a large number of kinematic points, in both S-wave and D-wave, within the elastic region. The technique is demonstrated with a calculation at a pion mass of 396 MeV, where the elastic scattering is found to be well described by a scattering length parameterisation.
@article{arxiv.1203.6041,
title = {S and D-wave phase shifts in isospin-2 pi pi scattering from lattice QCD},
author = {Jozef J. Dudek and Robert G. Edwards and Christopher E. Thomas},
journal= {arXiv preprint arXiv:1203.6041},
year = {2012}
}
Comments
Tables of little-group CGCs in ancillary file; v2: minor changes to reflect published version