Effects of Family Non-universal $Z^{\prime}$ Model in the angular observables of $B\to(\rho,a_{1})\mu^{+}\mu^{-}$ decays

TL;DR

This paper analyzes how a family non-universal $Z^{\'prime}$ model affects angular observables in specific $B$ meson decays, providing predictions that could help distinguish new physics effects in future collider experiments.

Contribution

It offers the first detailed predictions of angular observables in $B o ho,a_1$ muon decays within the non-universal $Z^{\'prime}$ framework, highlighting observable differences from the Standard Model.

Findings

Signatures of $Z^{\prime}$ are more prominent in $B\to\rho$ decays.

Predicted angular observables differ significantly from Standard Model expectations.

Future measurements can help identify or constrain the $Z^{\prime}$ model.

Abstract

We present the angular distribution of the four-fold $B\to\rho (\to\pi\pi)\mu^{+}\mu^{-}$ and $B\to a_{1}(\to\rho_{\parallel, \perp}\pi)\mu^{+}\mu^{-}$ decays both in the Standard Model and the family non-universal $Z^{\prime}$ model. At the quark level, these decays are governed by the $b\to d\mu^{+}\mu^{-}$ transition. Along with different angular observables, we also give predictions of differential branching ratios, forward-backward asymmetry, longitudinal polarization fraction of $\rho$, and $a_{1}$ mesons. Our analysis shows that the signatures of family non-universal $Z^{\prime}$ model are more distinct in the observables associated with the $B\to\rho(\to\pi\pi)\mu^{+}\mu^{-}$ decay, compared to that of the $B\to a_{1}(\to\rho_{\parallel, \perp}\pi)\mu^{+}\mu^{-}$ decay. Future measurements of the predicted angular observables, both at current and future high energy colliders, will add to the useful complementary data required to clarify the structure of the family non-universal $Z^{\prime}$ model in $|\Delta b|$=$|\Delta d|=1$ processes.