The asymmetries of the $B \to K^* \mu^+ \mu^-$ decay and the search of new physics beyond the Standard Model

TL;DR

This paper calculates asymmetries in the $B o K^* o uar u$ decay using improved QCD methods, compares predictions with experimental data, and explores implications for new physics beyond the Standard Model.

Contribution

It introduces a refined calculation of transition form factors using chiral correlators, enhancing the accuracy of decay asymmetry predictions for probing new physics.

Findings

Predictions align with experimental data for $q^2 \,\geq\, 6$ GeV$^2$

Different behaviors observed in the low $q^2$ region below 2 GeV$^2$

Application to $B\to K^*\nu\bar\nu$ decay observables within various models.

Abstract

In this paper, we compute the forward-backward asymmetry and the isospin asymmetry of the $B \to K^* \mu^+ \mu^-$ decay. The $B \to K^*$ transition form factors (TFFs) are key components of the decay. To achieve a more accurate QCD prediction, we adopt a chiral correlator for calculating the QCD light-cone sum rules for those TFFs with the purpose of suppressing the uncertain high-twist distribution amplitudes. Our predictions show that the asymmetries under the Standard Model and the Minimal Supersymmetric Standard Model with minimal flavor violation are close in shape for $q^2 \ge 6~{\rm GeV}^2$ and are consistent with the Belle, LHCb and CDF data within errors. When $q^2 < 2~{\rm GeV}^2$, their predictions behave quite differently. Thus a careful study on the $B \to K^* \mu^+ \mu^-$ decay within small $q^2$-region could be helpful for searching new physics beyond the Standard Model. As a further application, we also apply the $B \to K^*$ TFFs to the branching ratio and longitudinal polarization fraction of the $B\to K^*\nu\bar\nu$ decay within different models.