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 ${ 1/3}m_s \leq m_{ ud} \leq { 2/3}m_s$ whereas the valence quark masses satisfy ${ 1/2}m_{ sea} \leq m_{ val} \leq 2m_{ sea}$. 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 $\beta=5.1$ on $16^4$ lattices. ${ \cal O}(a)$ effects are taken into account by applying chiral perturbation theory for the Wilson lattice action as proposed by Rupak and Shoresh.
Categories: hep-lat