Renormalization of local quark-bilinear operators for N f=3 flavors of stout link nonperturbative clover fermions

Abstract

© 2015 American Physical Society. The renormalization factors of local quark-bilinear operators are computed nonperturbatively for Nf=3 flavors of stout link nonperturbative clover (SLiNC) fermions, with emphasis on the various procedures for the chiral and continuum extrapolations. The simulations are performed at a lattice spacing a=0.074fm, and for five values of the pion mass in the range of 290-465 MeV, allowing a safe and stable chiral extrapolation. Emphasis is given in the subtraction of the well-known pion pole which affects the renormalization factor of the pseudoscalar current. We also compute the inverse propagator and the Green's functions of the local bilinears to one loop in perturbation theory. We investigate lattice artifacts by computing them perturbatively to second order as well as to all orders in the lattice spacing. The renormalization conditions are defined in the RI′-MOM scheme, for both the perturbative and nonperturbative results. The renormalization factors, obtained at different values of the renormalization scale, are translated to the MS¯ scheme and are evolved perturbatively to 2 GeV. Any residual dependence on the initial renormalization scale is eliminated by an extrapolation to the continuum limit. We also study the various sources of systematic errors. Particular care is taken in correcting the nonperturbative estimates by subtracting lattice artifacts computed to one-loop perturbation theory using the same action. We test two different methods, by subtracting either the O(g2a2) contributions, or the complete (all orders in a) one-loop lattice artifacts.