Perturbative calculation of improvement coefficients toO(g2a)for bilinear quark operators in lattice QCD

We calculate the ${O(g}^{2}a)$ mixing coefficients of bilinear quark operators in lattice QCD using a standard perturbative evaluation of on-shell Green’s functions. Our results for the plaquette gluon action are in agreement with those previously obtained with the Schrödinger functional method. The coefficients are also calculated for a class of improved gluon actions having six-link terms.