$B_K$ Using Staggered Fermions: An Update

TL;DR

This paper provides updated results for the parameter $B_K$ using staggered fermions, highlighting reduced systematic errors and presenting a refined quenched value for degenerate quark kaons.

Contribution

It offers an improved calculation of $B_K$ with reduced scaling corrections and systematic errors using staggered fermions.

Findings

Quenched $B_K$ value: 0.825 ± 0.027 ± 0.023

Scaling corrections are of order $a^2$

Systematic error is reduced

Abstract

Improved results for $B_K$ are discussed. Scaling corrections are argued to be of $O(a^2)$, leading to a reduction in the systematic error. For a kaon composed of degenerate quarks, the quenched result is ${\widehat{B}_K} = 0.825 \pm 0.027 \pm 0.023$.