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

Abstract

We report on our studies of $B\to K_Jl^+l^-$ 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 $B\to K^*l^+l^-$ and $b\to s l^+l^-$ experimental data. Their impact on $B\to K_J^*l^+l^-$ 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.