Decay constant of $B_s$ and $B^*_s$ mesons from $\mathrm{N_f}=2$ lattice QCD

Rahul Balasubramamian , Benoît Blossier (1)

1 LPT - Laboratoire de Physique Théorique d'Orsay [Orsay]

We report on a two-flavor lattice QCD estimate of the $B_s$ and $B^*_s$ leptonic decays parameterized by the decay constants $f_{B_s}$ and $f_{B^*_s}$. 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 $f_{D_s}$ quoted by FLAG at $N_f=2$ and our ratio $\frac{f_{B_s}}{f_{D_s}}$, we obtain $f_{B_s}=215(10)(2)(^{+2}_{-5})$ MeV and $f_{B^*_s}/f_{B_s}=1.02(2)(^{+2}_{-0})$.

Mots clés: B/s: leptonic decay; quantum chromodynamics; lattice field theory; numerical calculations; quark: Wilson; fermion: clover; quark: flavor: 2; leptonic decay; decay constant; scaling; meson; quark: mass dependence

Domaines: Physique des Hautes Energies - Réseau [hep-lat]; Physique des Hautes Energies - Phénoménologie [hep-ph]

Rahul Balasubramamian, Benoît Blossier. Decay constant of $B_s$ and $B^*_s$ mesons from $\mathrm{N_f}=2$ lattice QCD. European Physical Journal C: Particles and Fields, 2020, 80 (5), pp.412. ⟨10.1140/epjc/s10052-020-7965-z⟩. ⟨hal-02431423⟩