Lattice simulations with $N_f=2+1$ improved Wilson fermions at a fixed strange quark mass

TL;DR

This paper presents a strategy for maintaining a fixed strange quark mass in lattice QCD simulations with $N_f=2+1$ Wilson fermions, addressing challenges from chiral symmetry breaking and renormalization differences.

Contribution

The authors develop and validate a method to keep the strange quark mass fixed in Wilson fermion lattice simulations, including determination of relevant renormalization constants and improvement coefficients.

Findings

Validated strategy for fixed strange quark mass in simulations

Determined key renormalization constants and improvement coefficients

Addressed chiral symmetry breaking effects in Wilson fermions

Abstract

The explicit breaking of chiral symmetry of the Wilson fermion action results in additive quark mass renormalization. Moreover, flavour singlet and non-singlet scalar currents acquire different renormalization constants with respect to continuum regularization schemes. This complicates keeping the renormalized strange quark mass fixed when varying the light quark mass in simulations with $N_f=2+1$ sea quark flavours. Here we present and validate our strategy within the CLS (Coordinated Lattice Simulations) effort to achieve this in simulations with non-perturbatively order-$a$ improved Wilson fermions. We also determine various combinations of renormalization constants and improvement coefficients.