SU(3) corrections to B → Dlν form factors at O(1M) Original Research Article

We compute the O(1M, ms) heavy quark and SU(3) corrections to Bs → Dseν form factors. In the limit of vanishing light quark mass, Bs → Dseν form factors are given in terms of the the B → Deν form factors, the leading order chiral parameter g, and two O(1M) chiral parameters g1 and g2. All the chiral parameters can be extracted, in principle, from other heavy meson decays. Analytic counterterms proportional to the strange quark mass are presented for completeness, but no predictive power remains when they are included. Anomalously large loop corrections warn of poor convergence of the heavy quark chiral symmetry expansion for these processes. This suggests that naive extrapolations of B → D form factors relying on heavy quark and chiral symmetries, as often used in monte carlo simulations of lattice QCD, may incur large errors.