Reappraisal of the minimal flavoured $Z^{\prime}$ scenario

TL;DR

This paper reexamines a minimal $Z'$ model with flavor-violating couplings to explain recent anomalies in lepton flavor universality and magnetic moments, while satisfying multiple experimental constraints.

Contribution

It identifies the minimal $Z'$ framework capable of explaining muon and electron magnetic moments and flavor anomalies, considering neutrino trident constraints and SU(2)_L violation.

Findings

The minimal $Z'$ model can simultaneously address muon and electron g-2 anomalies.

Neutrino trident data suggest additional SU(2)_L violation in leptonic couplings.

The model remains consistent with $R_{K^{(*)}}$, $B_s$ mixing, and angular observables.

Abstract

Recent results from the intensity frontier indicate the tantalizing possibility of violation in lepton flavour universality. In light of this we revisit the minimal phenomenological $Z'$ model taking in account both vectorial and axial-vectorial flavour violating couplings to the charged leptons. We make a systematic study to identify the minimal framework that can simultaneously explain the recent results on anomalous magnetic moment of muon and electron while remaining in consonance with $R_{K^{(*)}}$, $B^0_s-\bar{B^0_s}$ mixing and angular observables in the $B^+\to K^{+*} \mu^+\mu^-$ channel reported by the LHCb collaboration. We demonstrate that the neutrino trident data imply a further ${\rm SU(2)}_L$ violation in the leptonic couplings of the exotic $Z'$.