Decay constant of Bs and Bs∗ mesons from N f= 2 lattice QCD

Abstract

We report on a two-flavor lattice QCD estimate of the Bs and Bs∗ leptonic decays parameterized by the decay constants fBs and fBs∗. In addition to their relevance for phenomenology, their extraction has allowed us to investigate whether the “step scaling in mass” strategy is suitable with Wilson–Clover fermions to smoothly extrapolate quantities of the heavy-strange sector up to the bottom scale. From the central value of fDs quoted by FLAG at Nf= 2 and our ratio fBsfDs, we obtain fBs=215(10)(2)(-5+2) MeV and fBs∗/fBs=1.02(2)(-0+2).