Non-perturbative O(a) improvement of lattice QCD

Abstract

The coefficients multiplying the counterterms required for O($a$) improvement of the action and the isovector axial current in lattice QCD are computed non-perturbatively, in the quenched approximation and for bare gauge couplings $g_0$ in the range $0\le g_0\le 1$. A finite-size method based on the Schrödinger functional is employed, which enables us to perform all calculations at zero or nearly zero quark mass. As a by-product the critical hopping parameter ${\kappa }_c$ is obtained at all couplings considered.

Comments: typo in eq. (7.3) corrected; 26 pages, postscript file