Non-perturbative O(a) improvement of lattice QCD

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 less than or equal to g(0) less than or equal to 1. A finite-size method based on the Schrodinger 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. (C) 1997 Elsevier Science B.V.