Implications of new physics in $B \to K_1 \mu^+ \mu^-$ decay processes

TL;DR

This paper investigates potential signs of New Physics in rare B meson decays to axial vector mesons, analyzing how various operators affect observables like branching ratios and asymmetries within a model-independent framework.

Contribution

It provides a comprehensive, model-independent analysis of $B o K_1$ decays, incorporating form factors from light cone sum rules and exploring New Physics effects on multiple observables.

Findings

Enhanced understanding of $K_1$ mixing angle effects.

Predictions for deviations in observables due to New Physics.

Potential to identify NP signatures in future experiments.

Abstract

In recent times, several discrepancies at the level of $(2-3)\sigma$ have been observed in the decay processes mediated by flavour changing neutral current (FCNC) transitions $b \to s \ell^+ \ell^-$, which may be considered as the smoking-gun signal of New Physics (NP). These intriguing hints of NP have attracted a lot of attention and many attempts are made to look for the possible NP signature in other related processes, which are mediated through the same quark-level transitions. In this work, we perform a comprehensive analysis of the FCNC decays of $B$ meson to axial vector mesons $ K_1(1270)$ and $ K_1(1400)$, which are admixture of the $1^3P_1$ and $1^1P_1$ states $K_{1A}$ and $K_{1B}$, in a model independent framework. Using the $ B \to K_1$ form factors evaluated in the light cone sum rule approach, we investigate the rare exclusive semileptonic decays $ B \to K_1(1270) \mu^+ \mu^-$ and $ B \to K_1(1400) \mu^+ \mu^-$. Considering all the possible relevant operators for $b \to s \ell^+ \ell^-$ transitions, we study their effects on various observables such as branching fractions, lepton flavor universality violating ratio ($R_{K_1})$, forward-backward asymmetries, and lepton polarization asymmetries of these processes. These results will not only enhance the theoretical understanding of the mixing angle but also serve as a good tool for probing New Physics.