Extraction of B-s -> D-s(()*()) form factors from N-f=2 lattice QCD

We report on a two-flavor lattice QCD study of the B-s -> D-s and B-s -> D-s* in transitions parametrized, in the heavy quark limit, by the form factors G, and h(A1), h(A2), and h(A3), respectively. In the search for New Physics through tests of lepton flavor universality, B-s decay channels are complementary to the B decays widely studied at B factories and LHCb, while on the theory side they can be better controlled than the B-c and Lambda(b) decays. The purpose of this exploratory two-flavor study is, in preparation for future analyses of lattice QCD simulations with N-f > 2 and physical quark masses, to gain experience on a suitable method for a lattice extraction of form factors associated with b -> c currents that may yield tighter control over systematic effects like contamination from excited states and cutoff effects. We obtain the zero-recoil values G(Bs -> Ds)(1) = 1.03(14) and h(Bs -> Ds)*(1) =0.85(16).

Automated summary

We report on a two-flavor lattice QCD study of B-s -> D-s and B-s -> D-s* decays, parametrized by the form factors G, h(A1), h(A2), and h(A3) in the heavy quark limit. The results of this study can provide experience and insights for future lattice QCD simulations with N-f > 2 and physical quark masses.