$Bo Vell^_s16ell^-$ in the Standard Model from Light-Cone Sum Rules

Abstract

We present Bq_s13_s178594_s19_s13_s17961_s19, Bq_s13_s178594_s19_s13_s17969_s19, Bq_s13_s178594_s19K_s13_s178727_s19, Bs_s13_s178594_s19K_s13_s178727_s19 and Bs_s13_s178594_s19_s13_s17981_s19 form factors from light-cone sum rules using updated hadronic input parameters. It is argued that the, generally valid, equations of motion constrain the uncertainty of tensor-to-vector form factor ratios. This improves the prediction of zeros of helicity amplitudes which is of major importance for B_s13_s178594_s19K_s13_s178727_s19_s13_s178467_s19_s13_s178467_s19 angular observables. We provide easy-to-use fits to the LCSR results, including the full error correlation matrix, in all modes at low q2 as well as combined fits to LCSR and lattice results covering the entire kinematic range for Bq_s13_s178594_s19K_s13_s178727_s19, Bs_s13_s178594_s19K_s13_s178727_s19 and Bs_s13_s178594_s19_s13_s17981_s19. The error correlation matrix avoids the problem of overestimating the uncertainty in phenomenological applications. Using the new form factors and recent computations of non-factorisable contributions we provide Standard Model predictions for B_s13_s178594_s19K_s13_s178727_s19_s13_s17947_s19 as well as B_s13_s178594_s19K_s13_s178727_s19_s13_s178467_s19_s16_s13_s178467_s19_s13_s178722_s19 and Bs_s13_s178594_s19_s13_s17981_s19_s13_s17956_s19_s16_s13_s17956_s19_s13_s178722_s19 at low dilepton invariant mass. Employing our B_s13_s178594_s19(_s13_s17961_s19,_s13_s17969_s19) form factor results we extract the CKM element |Vub| from the semileptonic decays B_s13_s178594_s19(_s13_s17961_s19,_s13_s17969_s19)_s13_s178467_s19_s13_s17957_s19, and find good agreement with other exclusive determinations.