2014/11/03 by Zuohong Li, Zuo-Hong Li, Zong-Guo Si +6
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.1411.0466
31 pages, 7 figures, 7 tables, minor corrections made for typos and omissions
openalex publication_date 2014/11/03 · arxiv created 2014/11/09 · arxiv updated 2014/11/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
A new estimate is presented of the dileptonic B decays B→πℓ+ℓ-(ℓ=e,μ,τ) in naive factorization within the standard-model (SM) framework. Using a combination of several approaches, we investigate the behavior of the B→ π form factors in the entire region of the momentum transfer squared q2. For the vector and scalar form factors, we employ the light cone sum rule (LCSR) with a chiral current correlator to estimate, at twist-2 next-to-leading order (NLO) accuracy, their shapes in small and intermediate kinematical region. Then a simultaneous fit to a Bourrely-Caprini-Lellouch (BCL) parametrization is performed of the sum rule predictions and the corresponding lattice QCD (LQCD) results available at some high q2's. The same approach is applied for the tensor form factor, except that at large q2 we use as input the LQCD data on the corresponding B→ K form factor in combination with a SUF(3) symmetry breaking ansatz. Employing the fitted BCL parameterizations, we evaluate, as an illustrative example, several of the observables of the charged decay modes B-→π-ℓ+ℓ-, including the dilepton invariant mass distribution and branching ratio. For the dielectron and dimuon modes, the branching ratios are estimated at B(B-→π-e+e-)=(2.263+0.227-0.192)×10-8 and B(B-→π-μ+μ-)=(2.259+0.226-0.191) ×10-8. The latter shows an excellent agreement with the recent experimental measurement at LHCb and hence puts a stringent constraint on the contribution from possible new physics. We arrive at, for the ditau mode, B(B-→π-τ+τ-)=(1.017+0.118-0.139)×10-8, which is one order of magnitude larger than the existing theoretical predictions.