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m_b and f_Bs from a combination of HQET and QCD

Damiano Guazzini·Rainer Sommer·Nazario Tantalo
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Abstract

We compute the mass of the b-quark and the B_s meson decay constant in quenched lattice QCD using a combination of HQET and the standard relativistic QCD Lagrangian. We start from a small volume, where one can directly deal with the b-quark, and compute the evolution to a big volume, where the finite size effects are negligible through step scaling functions which give the change of the observables when L is changed to 2L. In all steps we extrapolate to the continuum limit, separately in HQET and in QCD for masses below m_b. The point m_b is then reached by an interpolation of the continuum results. With r_0=0.5 fm and the experimental B_s and K masses we find f_Bs=191(6) MeV and the renormalization group invariant mass M_b=6.89(11) GeV, translating into m_b(m_b)=4.42(7) GeV in the MS-bar scheme.

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Damiano Guazzini, Rainer Sommer, Nazario Tantalo. 2006-09-28. m_b and f_Bs from a combination of HQET and QCD. https://arxiv.org/abs/hep-lat/0609065

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