B →Vℓ+ℓ− in the Standard Model from light-cone sum rules

Aoife Bharucha, David M. Straub, Roman Zwicky

Research output: Contribution to journalArticlepeer-review

Abstract

We present B q ρ, B q ω, B q K , B s K and B s ϕ form factors from light-cone sum rules (LCSR) at O(αs) for twist-2 and 3 and O(α0s) for twist-4 with updated hadronic input parameters. Three asymptotic light-cone distribution amplitudes of twist-4 (and 5) 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 BK ℓℓ angular observables. We provide easy-to-use fits to the LCSR results, including the full error correlation matrix, in all modes at low q 2 as well as combined fits to LCSR and lattice results covering the entire kinematic range for B q K , B s K and B s ϕ. 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 BK γ as well as BK + and B s ϕμ + μ at low dilepton invariant mass. Employing our B → (ρ,ω) form factor results we extract the CKM element |V ub| from the semileptonic decays B → (ρ, ω)ℓν and find good agreement with other exclusive determinations.
Original languageEnglish
Article number98
Pages (from-to)1-62
Number of pages62
JournalJournal of High Energy Physics
VolumeN/A
DOIs
Publication statusPublished - 16 Aug 2016

Keywords

  • hep-ph

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