Sea quark effects in B_K from N_f=2 clover-improved Wilson fermions

Abstract

We report calculations of B_K using two flavours of dynamical clover-improved Wilson lattice fermions and look for dependence on the dynamical quark mass at fixed lattice spacing. We see some evidence for dynamical quark effects. In particular B_K decreases as the sea quark masses are reduced towards the up/down quark mass. Our meson masses are quite heavy and a firm prediction of B_K is a task for future simulations.

Comments: 3 pages, 1 figure. Talk given at Lattice2004(weak), Fermilab 21-26 June 2004