Quark mass dependence of masses and decay constants of the pseudo-Goldstone bosons in QCD

The dependence of the pseudo-scalar meson masses and decay constants on sea and valence quark masses is compared to next-to-leading order (NLO) chiral perturbation theory (ChPT). The numerical simulations with two light dynamical quark flavors are performed with the Wilson quark lattice action at gauge coupling beta = 5.1 and hopping parameters kappa = 0.176, 0.1765, 0.177 on a 16(4) lattice. O(a) lattice artifacts are taken into account by applying chiral perturbation theory for the Wilson lattice action. The values of the relevant combinations,of Gasser-Leutwyler constants L-4, L-5, L-6 and L-8 are estimated.