Electromagnetic mass difference on the lattice

TL;DR

This paper computes the electromagnetic mass difference of mesons using lattice QCD techniques, employing improved actions and extrapolations to compare with experimental data.

Contribution

It introduces a lattice QCD method to accurately calculate meson mass differences including electromagnetic effects, with chiral and continuum extrapolations.

Findings

Electromagnetic mass differences are consistent with experimental values.

Light quark masses are estimated with improved precision.

Finite size effects are analyzed and accounted for.

Abstract

We calculate electromagnetic mass difference of mesons using a method proposed by Duncan {\it et al}. The RG-improved gauge action and the non-compact Abelian gauge action are employed to generate configurations. Quark propagators in the range of $m_{PS}/m_{V}=0.76-0.51$ are obtained with the meanfield-improved clover quark action. Chiral and continuum extrapolations are performed and the results are compared with experiments. Finite size effects are also examined. Quark masses are extracted from the measured spectrum. Our preliminary values for light quark masses are $m_{u}^{\bar{MS}}(\mu =2 {GeV}) = 3.03(19)$ MeV, $m_{d}^{\bar{MS}}(\mu = 2 {GeV}) = 4.44(28)$ MeV, $m_{s}^{\bar{MS}}(\mu = 2 {GeV}) = 99.2(52)$ MeV.