Decay constant of $B_s$ and $B_s^{\ast }$ mesons from ${\mathrm{N}}_{\mathrm{f}}=2$ lattice QCD}

Abstract

We report on a two-flavor lattice QCD estimate of the $B_s$ and $B_s^{\ast }$ leptonic decays parameterized by the decay constants $f_{B_s}$ and $f_{B_s^{\ast }}$. In addition to their relevance for phenomenology, their extraction has allowed us to investigate whether the "step scaling in mass" strategy is suitable with Wlilson-Clover fermions to smoothly extrapolate quantities of the heavy-strange sector up to the bottom scale. From the central value of $f_{D_s}$ quoted by FLAG at $N_f=2$ and our ratio $\frac{f_{B_s}}{f_{D_s}}$, we obtain $f_{B_s}=215(10)(2){(}_{-5}^{+2})$ MeV and $f_{B_s^{\ast }}/f_{B_s}=1.02(2){(}_{-0}^{+2})$.

Comments: 17 pages, 5 figures; published version