Electromagnetic effects on the light hadron spectrum

TL;DR

This paper investigates electromagnetic effects on light mesons using lattice QCD with quenched photons, analyzing how well chiral perturbation theory models these effects and implications for quark masses.

Contribution

It provides new lattice QCD results at small lattice spacings and large volumes, assessing electromagnetic impacts on the light hadron spectrum.

Findings

Electromagnetic effects are significant for light meson mass splittings.

Chiral perturbation theory describes the results well at NLO.

Implications for light quark mass determinations are discussed.

Abstract

For some time, the MILC Collaboration has been studying electromagnetic effects on light mesons. These calculations use fully dynamical QCD, but only quenched photons, which suffices to NLO in XPT. That is, the sea quarks are electrically neutral, while the valence quarks carry charge. For the photons we use the non-compact formalism. We have new results with lattice spacing as small as 0.045 fm and a large range of volumes. We consider how well chiral perturbation theory describes these results and the implications for light quark masses