Quark masses using twisted-mass fermion gauge ensembles

We present a calculation of the up, down, strange, and charm quark masses performed within the lattice QCD framework. We use the twisted-mass fermion action and carry out simulations that include in the sea two light mass-degenerate quarks, as well as the strange and charm quarks. In the analysis, we use gauge ensembles simulated at three values of the lattice spacing and with light quarks that correspond to pion masses in the range from 350 MeV to the physical value, while the strange and charm quark masses are tuned approximately to their physical values. We use several quantities to set the scale in order to check for finite lattice spacing effects, and in the continuum limit, we get compatible results. The quark mass renormalization is carried out nonperturbatively using the (modified) Regularization Independent Momentum Subtraction (RI0-MOM) method converted into the MS scheme. For the determination of the quark masses, we use physical observables from both the meson and the baryon sectors, obtaining mud = 3.636(66) ("60���57) MeV and ms = 98.7(2.4) (+4.0���3.2) MeV in the MS(2 GeV) scheme and mc = 1036(17) (+15���8) MeV in the MS(3 GeV) scheme, where the first errors are statistical and the second ones are combinations of systematic errors. For the quark mass ratios, we get ms/mud = 27.17(32) (+56���38) and mc/ms =11.48(12) (+25���19).