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

TL;DR

This paper studies the decay process $B o K_2^* l^+ l^-$ within the Standard Model and new physics models, deriving angular distributions and predicting observables to guide future experimental searches, while updating constraints on new physics parameters.

Contribution

It provides the first detailed analysis of $B o K_2^* l^+ l^-$ decay including angular distributions and explores effects of new physics scenarios on observables.

Findings

Predicted branching ratios and asymmetries for $B o K_2^* l^+ l^-$

Identified potential deviations in forward-backward asymmetry zero-crossing points due to new physics

Updated constraints on Wilson coefficients from existing $B o K^* l^+ l^-$ data

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 $B_s\to f_2'(1525)(\to K^+K^-) l^+l^-$.