Quark mass dependence of pseudo-scalar masses and coupling constants qq+q Collaboration

Abstract The dependence of pseudo-scalar masses and decay constants on the sea and valence quark masses is investigated in the pseudo- Goldstone boson sector of QCD with two light quark flavours. The sea quark masses are at present in the range 1 3 m s ≤ m ud ≤ 2 3 m s whereas the valence quark masses satisfy 1 2 m sea ≤ m val ≤ 2m sea . The values of the Gasser-Leutwyler low energy constants L 4 , L 5 , L 6 and L 8 are estimated. The computation is done with the Wilson-quark lattice action at gauge coupling β = 5.1 on 16 4 lattices. O (a) effects are taken into account by applying chiral perturbation theory for the Wilson lattice action as proposed by Rupak and Shoresh.