The Kaon B-parameter in quenched QCD

Abstract

I report on a recent determination by the ALPHA collaboration of the kaon B-parameter using lattice QCD with Wilson type quarks. An effort is made to control all systematic errors except for the quenched approximation. The preliminary result for the renormalization group invariant parameter is ${\hat{B}}_K=0.834(37)$, which translates to $B_K^{M}Sbar(2GeV)=0.604(27)$ in the MSbar scheme with anticommuting ${\gamma }_5$.

Comments: 4 pages, parallel talk at International Conference on QCD and Hadronic Physics, Beijing, June 2005