9 research outputs found
B →Vℓ+ℓ− in the Standard Model from light-cone sum rules
We present , , , and
form factors from light-cone sum rules (LCSR) at
for twist-2 and 3 and for
twist-4 with updated hadronic input parameters. Three asymptotic light-cone
distribution amplitudes of twist- (and ) are determined, necessary for
the form factors to obey the equations of motion. It is argued that the latter
constrain the uncertainty of tensor-to-vector form factor ratios thereby
improving the prediction of zeros of helicity amplitudes of major importance
for angular observables. We provide easy-to-use fits to the
LCSR results, including the full error correlation matrix, in all modes at low
as well as combined fits to LCSR and lattice results covering the entire
kinematic range for , and . 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 as well as and
at low dilepton invariant mass. Employing our form factor results we extract the CKM element
from the semileptonic decays and
find good agreement with other exclusive determinations.Comment: 64 pages, 7 figures, 15 tables. v3: Minor clarifications, numerics
unchanged. Matches version published in JHE