Branching ratios, forward-backward asymmetries and angular distributions of $B\to K_2^*l^+l^-$ in the standard model and new physics scenarios

Abstract

We analyze the $B\to K_2^*(\to K\pi)l^+l^-$ (with $l=e,\mu,\tau$) decay in the standard model and two new physics scenarios: vector-like quark model and family non-universal $Z'$ model. We derive its differential angular distributions, using the recently calculated form factors in the perturbative QCD approach. Branching ratios, polarizations, forward-backward asymmetries and transversity amplitudes are predicted, from which we find a promising prospective to observe this channel on the future experiment. We also update the constraints on effective Wilson coefficients and/or free parameters in these two new physics scenarios by making use of the experimental data of $B\to K^*l^+l^-$ and $b\to sl^+l^-$. Their impact on $B\to K_2^*l^+l^-$ is subsequently explored and in particular the zero-crossing point for the forward-backward asymmetry in these new physics scenarios can sizably deviate from the SM scenario. In addition we also generalize the analysis to a similar mode $B_s\to f_2'(1525)(\to K^+K^-) l^+l^-$.