Non-perturbative renormalization constants and light quark masses

Abstract

We present the results of an extensive non-perturbative calculation of the renormalization constants of bilinear quark operators for the non-perturbativelyO(a)-improved Wilson action. The results are obtained at four values of the lattice coupling, by using the RI/MOM and the Ward identities methods. A new non-perturbative renormalization technique, which is based on the study of the lattice correlation functions at short distance in x-space, is also numerically investigated. We then use our non-perturbative determination of the quark mass renormalization constants to compute the values of the strange and the average up/down quark masses. After performing an extrapolation to the continuum limit, we obtain M s MS¯(2GeV= (106 ± 2 ± 8) MeV and m l MS¯(2 GeV) = (4.4 ± 0.1 ± 0.4) MeV.