The Mass of the b Quark from Lattice NRQCD

TL;DR

This paper calculates the b quark mass using lattice NRQCD and static limit techniques, providing a preliminary value and estimating effects of dynamical quarks, with results relevant for understanding quark masses in QCD.

Contribution

The paper introduces a lattice NRQCD method to determine the b quark mass in the ar{MS} scheme, including the impact of dynamical quarks, with improved precision in the static quark self-energy.

Findings

Preliminary ar{m_b}(\u001bar{m_b})=4.34(7) GeV at n_f=0.

Quark mass decreases by about 70 MeV with two dynamical quark flavors.

Self energy known to O(lpha^3) in quenched approximation.

Abstract

We present results for the mass of the $b$ quark in the $\bar{MS}$ scheme obtained by calculating the binding energy of the $B$ meson in the static limit. The self energy of a static quark, $E_0^\infty$ needed for this purpose, is now known to $O(\alpha^3)$ in the quenched approximation. We find a {\it preliminary} value of $\bar{m_b}(\bar{m_b})=4.34(7)$ GeV at $n_f=0$. The error is dominated by the remaining uncertainty in $E_0^\infty$. In addition, using $E_0^\infty$ at $O(\alpha^2)$, we estimate that the quark mass is reduced by approximately 70 MeV when two flavours of dynamical quarks are introduced.