A nonperturbative determination of c_A and the scaling of f_pi and m^(MSbar)

We calculate the $O(a)$ improvement coefficient for the axial-vector current using the nonperturbative method proposed by the LANL group. Results for the coefficient in the range $\beta=5.93$ to 6.2 are presented. We find $c_A$ is close to the 1-loop tadpole-improved perturbative value. In addition, scaling of the pseudoscalar decay constant and renormalised quark mass is improved compared to that obtained using the (larger) $c_A$ values obtained by the ALPHA collaboration.