Non-perturbative renormalization for a renormalization group improved gauge action

Renormalization constants of vector (ZV) and axial-vector (ZA) currents are determined non-perturbatively in quenched QCD for a renormalization group improved gauge action and a tadpole improved clover quark action using the Schrödinger functional method. Non-perturbative values of ZV and ZA turn out to be smaller than the one-loop perturbative values by O(10%) at a-1 ≈ 1 GeV. A sizable scaling violation of meson decay constants fπ and fρ observed with the one-loop renormalization factors remains even with non-perturbative renormalization