Chiral-symmetry breaking and light-quark masses in lattice QCD

The chiral order parameter and the masses of the pseudoscalar and vector mesons are computed in lattice QCD neglecting fermion-polarization effects on lattices of size up to 8×8×8×16. Five values of the gauge coupling constants are considered and the results are compared with the weak-coupling asymptotic-freedom predictions. Estimates for the values of the light-quark masses are presented and their scaling behavior is studied. A preliminary study of the spatial-size dependence of physical quantities is presented. Finite-size scaling methods are used to compare the results for the vector-pseudoscalar-meson spin splittings on the larger lattice with results on a 4×4×4×16 and 6×6×6×12 lattice. This allows one to penetrate deeper in the weak-coupling region. Around $g^2$=1 the results would suggest significant deviations from two-loop asymptotic-freedom scaling.