B_K from Two-flavor Dynamical Domain Wall Fermions

TL;DR

This paper presents preliminary results for the kaon bag parameter $B_K$ calculated using two-flavor dynamical domain wall fermions in lattice QCD, with implications for understanding CP violation.

Contribution

It provides new lattice QCD calculations of $B_K$ with dynamical fermions using domain wall fermions, including extrapolation to the physical kaon point.

Findings

$B_K^{ar{MS}}(2 ext{ GeV}) = 0.503(20)$

Simulations used three dynamical quark masses on $16^3 imes 32$ lattices

Results are based on measurements from approximately 70 lattices per mass

Abstract

We report preliminary results from an ongoing calculation of $B_K$ for $N_f=2$ dynamical QCD with domain wall fermions. Simulations have been done with three dynamical quark masses on $16^3 \times 32$ volumes with $L_s = 12$, where the lattice spacing is $a^{-1} = 1.81(6)$ GeV. Using measurements on $\sim 70$ lattices for each dynamical mass and extrapolating $\mdyn=\mval$ to the kaon point, we find $B_K^{\rm \bar{MS}}(\mu=2{\rm GeV}) = 0.503(20)$.