Lattice QCD Calculation of the Pion Mass Splitting

We use the infinite volume reconstruction method to calculate the charged and neutral pion mass difference. The hadronic tensor is calculated using lattice QCD and then combined with an analytic photon propagator, and the mass splitting is calculated with exponentially suppressed finite-volume errors. The calculation is performed using six gauge ensembles generated with 2 + 1-flavor domain wall fermions, and five ensembles are at the physical pion mass. Both Feynman and Coulomb gauges are adopted in the calculation and agree well when the lattice spacing approaches zero. After performing the continuum extrapolation and examining the residual finite-volume effects, we obtain the pion mass splitting Delta m pi = 4.534(42)stat(43)sys MeV, which agrees well with experimental measurements.

Automated summary

In this study, the infinite volume reconstruction method is used to calculate the mass difference between charged and neutral pions. The hadronic tensor is computed using lattice QCD and combined with an analytic photon propagator. By performing a continuum extrapolation and examining finite-volume effects, the calculated pion mass splitting is found to agree well with experimental measurements.