Bd,s→ρ,ω,K*,ϕdecay form factors from light-cone sum rules reexamined

Abstract

Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We present an improved calculation of B ! light vector form factors from light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading order twist-4 corrections. The total theoretical uncertainty of our results at zero momentum transfer is typically 10% and can be improved, at least in part, by reducing the uncertainty of hadronic input parameters. We present our results in a way which details the dependence of the form factors on these parameters and facilitates the incorporation of future updates of their values from, e.g., lattice calculations. We also give simple and easy-to-implement parametrizations of the q 2 dependence of the form factors which are valid in the full kinematical regime of q 2 .

B → K ∗ ν ν ¯ $$ B\to {K}^{\left(\ast \right)}\nu \overline{\nu} $$ decays in the Standard Model and beyond

“…For the B → K ( * ) νν transitions, factorization is exact, so a measurement of the decay rates would allow in principle to measure the form factors. In the last two years, lattice computations of B → K and B → K * form factors have become available [3,4] that are valid at large q 2 of the neutrino pair and which complement the existing results within light-cone sum rules (LCSR) [5][6][7], valid at low and intermediate q 2 . Combining these two sources of information, we will give SM predictions for the observables valid in the entire kinematic range, not relying on model-dependent extrapolations.…”

“…In the SM, they can be written as 6) where the factor of 3 stems from the sum over neutrino flavours,…”

“…Both for B → K and B → K * , lattice computations have become available recently [3,4], that are valid at large q 2 . At low q 2 , we make use of the results from light-cone sum rules [5,6]. Since the form factors have to be smooth functions of q 2 , one can obtain expressions valid in the whole kinematical range relevant for B → K ( * ) νν by performing a combined fit to lattice and LCSR results.…”

Future prospects for the determination of the Wilson coefficient $ C_{{^{{7\gamma }}}}^{\prime } $

“…which in practice we vary between (0.17 ÷ 0.23) GeV −1 [66][67][68]. For the ratio of the tensor form factors we use the approximation…”

Direct determination of Wilson coefficients using B0 → K∗0μ+μ− decays

“…The form factors require non-perturbative calculations and are determined using light cone sum rules (LCSR) [11,81,82] or lattice calculations [12,13]. This paper uses the full form factor approach with the results from ref.…”