Renormalized quark masses using gradient flow

Abstract: We propose a new and simple method for determining the renormalized quark masses from lattice simulations. Renormalized quark masses are an important input to many phenomenological applications, including searching/modeling physics beyond the Standard Model. The non-perturbative renormalization is performed using gradient flow combined with the short-flow-time expansion that is improved by renormalization-group (RG) running to match to the $\overline{\text{MS}}$-scheme. RG running connects the lattice scale to higher energies thus improving the $\overline{\text{MS}}$-scheme matching. Implementing the RG running perturbatively, we demonstrate this method works reliably at least up to the charm-quark mass and is not exhibiting any signs of the usual ``window problem''. Using \abbrev{RBC/UKQCD}'s (2+1)-flavor Shamir domain-wall fermion ensembles with Iwasaki gauge action, we find $m_s^\overline{\text{MS}}(\mu=2 \text{ GeV}) = 90(3)$ MeV and $m_c^\overline{\text{MS}}(\mu=3 \text{ GeV}) = 975(10)$ MeV. These results predict the scale-independent ratio $m_c/m_s= 12.0(4)$. Generalization to other observables is possible, providing an efficient approach to determine non-perturbatively renormalized fermionic observables like form factors or bag parameters from lattice simulations.