Forward-backward asymmetry of $B\to K_J{l}^{+}{l}^{-}$ decays in SM and new physics models

Abstract

We report on our studies of $B\to K_J{l}^{+}{l}^{-}$ in the standard model and several new physics variations, with $K_J$ denoting a kaonic resoanance. In terms of helicity amplitudes, we derive a compact form for the full angular distributions, and use them to calculate the branching ratios, forward-backward asymmetries and polarizations. We have updated the constraints on effective Wilson coefficients and/or free parameters in these new physics scenarios by making use of the $B\to K^{\ast }{l}^{+}{l}^{-}$ and $b\to s{l}^{+}{l}^{-}$ experimental data. Their impact on $B\to K_J^{\ast }{l}^{+}{l}^{-}$ is subsequently explored and in particular the zero-crossing point for forward-backward asymmetry in new physics scenarios can sizably deviate from the standard model.

Comments: 4 pages, latex, talk presented at the 47th Rencontres de Moriond - QCD conference, La Thuile and Fourth Workshop on Theory, Phenomenology and Experiments in Flavour Physics, Capri, Italy, 2012