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

TL;DR

This study investigates how sea quark effects influence the B_K parameter using N_f=2 dynamical clover-improved Wilson fermions, observing a decrease in B_K with lighter sea quarks, but with heavy mesons limiting definitive conclusions.

Contribution

First lattice QCD calculation of B_K with dynamical Wilson fermions exploring sea quark mass dependence.

Findings

B_K decreases as sea quark mass approaches the up/down quark mass.

Evidence suggests dynamical quark effects impact B_K.

Heavy meson masses limit precise predictions.

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.