We present first results for the step scaling function sigma_P of the renormalization factor Z_P of the pseudoscalar density. The simulations are performed within the framework of the Schroedinger functional with two flavors of O(a) improved Wilson fermions. The knowledge of sigma_P is required to compute the renormalization group invariant quark masses. We also study the performance of a variant of the HMC algorithm using two pseudofermion fields.
@article{arxiv.hep-lat/0209025,
title = {Running quark mass in two flavor QCD},
author = {F. Knechtli and M. Della Morte and J. Rolf and R. Sommer and I. Wetzorke and U. Wolff},
journal= {arXiv preprint arXiv:hep-lat/0209025},
year = {2009}
}