$B_s$-$\bar{B_s}$ mixing from lattice QCD

TL;DR

This paper calculates the $B_s$-$ar{B_s}$ mixing amplitude using lattice QCD with static HQET and Neuberger light quarks, providing a precise value for the bag parameter in the quenched approximation.

Contribution

It presents a lattice QCD computation of the $B_s$-$ar{B_s}$ mixing matrix element in the static limit with Neuberger quarks, including NLO matching to the $ar{ m MS}$ scheme.

Findings

Computed $ ext{B}_s$ mixing parameter $oxed{0.940(16)(22)}$ in the $ar{ m MS}$ scheme.

Used quenched approximation with static HQET and Neuberger light quarks.

Provided a key input for Standard Model predictions of $B_s$ mixing.

Abstract

We study the $B^0_s-\bar{B^0_s}$ mixing amplitude in Standard Model by computing the relevant hadronic matrix element in the static limit of lattice HQET with the Neuberger light quark action. In the quenched approximation, and after matching to the $\bar{\rm MS}$ scheme in QCD, we obtain $\hat{B}^{\bar{\rm MS},{\rm NLO}}_{B_s}(m_b)=0.940(16)(22)$.