A proposal for B-physics on current lattices

Abstract

A method to extract B-physics parameters (b-quark mass and f B , f Bs decay constants) from currently available lattice data is presented and tested. The approach is Open Access doi:10.1007/JHEP04 (2010)049 JHEP04 (2010)049 based on the idea of constructing appropriate ratios of heavy-light meson masses and decay constants, respectively, possessing a precisely known static limit, and evaluating them at various pairs of heavy quark masses around the charm. Via a smooth interpolation in the heavy quark mass from the easily accessible charm region to the asymptotic point, Bphysics parameters are computed with a few percent (statistical + systematic) error using recently produced N f = 2 maximally twisted Wilson fermions data.

Lattice QCD determination of m b , f B and f Bs with twisted mass Wilson fermions

“…Our results for the b quark mass in the MS scheme and for the decay constants which are in good agreement with our previous results [4,5], but which have smaller uncertainties. In particular, with respect to the result m b (m b ) = 4.63 (27) GeV of [4], we obtain for the b quark mass a central value which is smaller by approximately one standard deviation and a reduction of the uncertainty by almost a factor two, mainly because of the improvement in the determination of the quark mass renormalization constant.…”

“…In particular, with respect to the result m b (m b ) = 4.63 (27) GeV of [4], we obtain for the b quark mass a central value which is smaller by approximately one standard deviation and a reduction of the uncertainty by almost a factor two, mainly because of the improvement in the determination of the quark mass renormalization constant. As a byproduct of the analysis we also obtain the results for the f D and f Ds decay constants…”

“…In [4] we performed an exploratory calculation of the b quark mass and the decay constants f B and f Bs by introducing suitable ratios having an exactly known static limit. In [5] a more standard method [6] was applied, using lattice QCD data with the heavy quark mass ranging from the charm region up to more than 3 GeV, together with the information coming from a calculation in the static limit point.…”

“…We now proceed to describe the two approaches adopted in the present work to study the B-physics observables, namely the ratio method of [4] and the interpolation method.…”

“…The b quark mass is obtained by implementing the ratio method of [4], briefly recalled hereafter. The method is suggested by the HQET asymptotic behavior of the heavy-light meson mass M hℓ , …”