Scaling property of domain-wall QCD in perturbation theory

We estimate the lattice artifacts in loop corrections perturbatively for domain-wall QCD with an infinite number of extra flavors. We find that there appear no O(a) errors in renormalization factors of the quark wave function, mass, and quark bilinear operators at the one- and two-loop levels with off-shell quark momentum. Our proof is based on the even- or oddness of the quantum correction in terms of the quark external momentum and mass, and it can be extended to any loop level.