Lattice QCD determination of m_b, f_B and f_Bs with twisted mass Wilson fermions

TL;DR

This paper uses lattice QCD with twisted mass Wilson fermions to accurately determine the b quark mass and B meson decay constants, employing two complementary methods that agree well, and also provides results for D meson decay constants.

Contribution

It introduces two novel methods for determining the b quark mass and decay constants using lattice QCD, with results validated through their agreement.

Findings

b quark mass m_b(m_b)=4.29(14) GeV

Decay constants f_B=195(12) MeV, f_Bs=232(10) MeV

Additional results for D meson decay constants

Abstract

We present a lattice QCD determination of the b quark mass and of the B and B_s decay constants, performed with N_f=2 twisted mass Wilson fermions, by simulating at four values of the lattice spacing. In order to study the b quark on the lattice, two methods are adopted in the present work, respectively based on suitable ratios with exactly known static limit and on the interpolation between relativistic data, evaluated in the charm mass region, and the static point, obtained by simulating the HQET on the lattice. The two methods provide results in good agreement. For the b quark mass in the MSbar scheme and for the decay constants we obtain m_b(m_b)=4.29(14) GeV, f_B=195(12) MeV, f_Bs=232(10) MeV and f_Bs/f_B=1.19(5). As a byproduct of the analysis we also obtain the results for the f_D and f_Ds decay constants: f_D=212(8) MeV, f_Ds=248(6) MeV and f_Ds/f_D=1.17(5).