A closer look at observables from exclusive semileptonic B → (π, ρ)ℓν ℓ decays

Abstract

Abstract This article analyses the available inputs in B → πℓν ℓ and B → ρℓν ℓ decays which include the measured values of differential rate in different q 2-bins (lepton invariant mass spectrum), lattice, and the newly available inputs on the relevant form-factors from the light-cone sum rules (LCSR) approach. We define different fit scenarios, and in each of these scenarios, we predict a few observables in the standard model (SM). For example, R M = B B → M ℓ i ν ℓ i B B → M ℓ j ν ℓ j , R ℓ j ℓ i M = B B → ℓ i ν ℓ i B B → M ℓ j ν ℓ j $$ R(M)=\frac{\mathcal{B}\left(B\to M{\ell}_i{\nu}_{\ell_i}\right)}{\mathcal{B}\left(B\to M{\ell}_j{\nu}_{\ell_j}\right)},{R}_{\ell_j}^{\ell_i}(M)=\frac{\mathcal{B}\left(B\to {\ell}_i{\nu}_{\ell_i}\right)}{\mathcal{B}\left(B\to M{\ell}_j{\nu}_{\ell_j}\right)} $$ with M = π or ρ and ℓ i,j = e, μ or τ. We also discuss the new physics (NP) sensitivities of all these observables and obtain bounds on a few NP Wilson coefficients in b → uτντ decays using the available data. We have noted that the data at present allows sizeable NP contributions in this mode. Also, we have predicted a few angular observables relevant to these decay modes.

Keywords

• B physics
• Beyond Standard Model
• Flavor physics
• Other experiments