Journal of High Energy Physics (Mar 2023)

First results on QCD+QED with C * boundary conditions

  • The RCstar collaboration,
  • Lucius Bushnaq,
  • Isabel Campos,
  • Marco Catillo,
  • Alessandro Cotellucci,
  • Madeleine Dale,
  • Patrick Fritzsch,
  • Jens Lücke,
  • Marina Krstić Marinković,
  • Agostino Patella,
  • Nazario Tantalo

DOI
https://doi.org/10.1007/JHEP03(2023)012
Journal volume & issue
Vol. 2023, no. 3
pp. 1 – 42

Abstract

Read online

Abstract Accounting for isospin-breaking corrections is critical for achieving subpercent precision in lattice computations of hadronic observables. A way to include QED and strong-isospin-breaking corrections in lattice QCD calculations is to impose C⋆ boundary conditions in space. Here, we demonstrate the computation of a selection of meson and baryon masses on two QCD and five QCD+QED gauge ensembles in this setup, which preserves locality, gauge and translational invariance all through the calculation. The generation of the gauge ensembles is performed for two volumes, and three different values of the renormalized fine-structure constant at the U-symmetric point, corresponding to the SU(3)-symmetric QCD in the two ensembles where the electromagnetic coupling is turned off. We also present our tuning strategy and, to the extent possible, a cost analysis of the simulations with C⋆ boundary conditions.

Keywords