The Kaon B-parameter from Quenched Domain-Wall QCD

TL;DR

This paper reports a lattice QCD calculation of the kaon B-parameter using quenched domain-wall fermions, non-perturbative renormalization, and scaling analysis across two lattice spacings, providing a precise value with error estimates.

Contribution

First quenched lattice QCD determination of B_K with non-perturbative renormalization and scaling analysis using domain-wall fermions and improved gauge action.

Findings

B_K(MS,NDR,mu=2GeV)=0.563 with combined errors

Performed scaling study on two lattice spacings

Compared quenched results with previous dynamical quark calculations

Abstract

We present numerical results for the kaon B-parameter, B_K, determined in the quenched approximation of lattice QCD. Our simulations are performed using domain-wall fermions and the renormalization group improved, DBW2 gauge action which combine to give quarks with good chiral symmetry at finite lattice spacing. Operators are renormalized non-perturbatively using the RI/MOM scheme. We study scaling by performing the simulation on two different lattices with a^{-1} = 1.982(30) and 2.914(54) GeV. We combine this quenched scaling study with an earlier calculation of B_K using two flavors of dynamical, domain-wall quarks at a single lattice spacing to obtain B_K(MS,NDR,mu=2GeV)=0.563(21)(39)(30), were the first error is statistical, the second systematic (without quenching errors) and the third estimates the error due to quenching.