Baryon masses from full QCD+QED${}_\text{C}$ simulations

TL;DR

This paper reports preliminary lattice QCD+QED simulations for baryon masses, demonstrating that including QED effects is feasible without gauge fixing or perturbation theory, thus supporting future more physical simulations.

Contribution

It introduces a method to compute baryon masses with QED effects on a single ensemble without gauge fixing, showing promising preliminary results.

Findings

Baryon masses can be calculated with satisfactory precision including QED effects.

QED effects can be incorporated without gauge fixing or perturbation theory.

The approach is promising for future simulations closer to physical parameters.

Abstract

In these proceedings we present preliminary results for the masses of the proton, neutron and $\Omega^-$ baryons obtained from QCD+QED lattice simulations performed with four dynamical quarks using C$^*$ boundary conditions. These results are part of the ongoing effort of the RC${}^*$ collaboration discussed in the companion proceedings, and have been obtained on a single ensemble in which the renormalised electromagnetic coupling is $\alpha_{\text{em}}\sim 0.04$, the physical volume is $L\sim 1.7$ fm and the masses of the four dynamical quarks have been tuned at the $U$--spin symmetric point $m_d=m_s$. We demonstrate on this unphysical ensemble that baryon masses can be calculated with satisfactory precision when including QED without the need for gauge--fixing and perturbation theory. This makes us confident in the effectiveness of the strategy presented here also in the case of simulations closer to the physical point.