Using the Coulomb gauge formulation of QED we present a lattice QCD procedure to calculate the π+π+ scattering phase shift including the effects of the Coulomb potential which appears in this formulation. The approach described here incorporates the effects of relativity and avoids finite-volume corrections that vanish as a power of the volume in which the lattice calculation is performed. This is the first step in developing a complete lattice QCD calculation of the electromagnetic and isospin-breaking light-quark mass contributions to ε′, the parameter describing direct CP violating effects in KL→ππ decay.
@article{arxiv.2111.04668,
title = {$\pi-\pi$ scattering, QED and finite-volume quantization},
author = {Norman Christ and Xu Feng and Joseph Karpie and Tuan Nguyen},
journal= {arXiv preprint arXiv:2111.04668},
year = {2022}
}