Perturbative calculation ofO(a)improvement coefficients

We compute several coefficients needed for $O\left(a\right)\mathrm{}$ improvement of currents in perturbation theory, using the Brodsky-Lepage-Mackenzie prescription for choosing an optimal scale $q^{*}.$ We then compare the results to non-perturbative calculations. Normalization factors of the vector and axial vector currents show good agreement, especially when allowing for small two-loop effects. On the other hand, there are large discrepancies in the coefficients of $O\left(a\right)\mathrm{}$ improvement terms. We suspect that they arise primarily from power corrections inherent in the nonperturbative methods.