2006/10/04 by Pietro Colangelo, P. Colangelo, F. De Fazio +4 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Electron #Hadron #Helicity #Lepton #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.74.115006
published as Phys.Rev.D74:115006,2006 · RevTeX, 23 pages, 9 figures. High resolution figures available upon request
arxiv created 2006/10/04 · openalex publication_date 2006/12/08 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the branching fractions and the lepton polarization asymmetries of rare B\ensuremath→Xs\ensuremathτ+\ensuremathτ^\ensuremath- and B\ensuremath→K(*)\ensuremathτ+\ensuremathτ^\ensuremath- modes within the standard model and in the Appelquist-Cheng-Dobrescu model, which is a New Physics scenario with a single universal extra dimension. In particular, we investigate the sensitivity of the observables to the radius R of the compactified extra dimension, which is the only new parameter in this New Physics model. For the exclusive transitions we study the uncertainties due to the hadronic matrix elements using two set of form factors, finding that in many cases such uncertainties are small. In particular, we show that the \ensuremathτ^\ensuremath- polarization asymmetries become free of hadronic uncertainties if Large Energy relations for the form factors, valid for low momentum transfer to the lepton pair, are used. We also consider K* helicity fractions and their sensitivity to the compactification parameter.