Neutrino masses and magnetic moments of electron and muon in the Zee Model

TL;DR

This paper investigates the Zee Model to explain the electron and muon anomalous magnetic moments, neutrino masses, and potential new physics signals, while ensuring consistency with experimental constraints and exploring collider detection prospects.

Contribution

It introduces two minimal flavor structures within the Zee Model that simultaneously address lepton AMMs and neutrino oscillations, and analyzes their experimental viability.

Findings

Neutral Higgs mass range: 10-300 GeV or 1-30 GeV.

Charged scalars as light as 100 GeV can induce significant nonstandard interactions.

Parameter space allows sizable muon EDM contributions and future collider detection potential.

Abstract

We explore parameter space in the Zee Model to resolve the long-standing tension of the electron and muon anomalous magnetic moment (AMM). The model comprises a second Higgs doublet and a charged singlet at electroweak scale and generates Majorana neutrino masses at one-loop level; the neutral partner of the $SU(2)_L$ doublet contributes to the AMM of electron and muon via one loop and two-loop corrections. We propose two minimal flavor structures that can explain these anomalies while fitting the neutrino oscillation data. We find that the neutral Higgs resides in the mass range of roughly 10-300 GeV or 1-30 GeV, depending on the flavor structures. The model is consistent with constraints from colliders, electroweak precision data, and lepton flavor violation. To be comprehensive, we examine the constraints from the electric dipole moment (EDM) and find a region of parameter space that gives a sizable contribution to muon EDM while simultaneously giving corrections to muon AMM. In addition to the light scalar, the two charged scalars with masses as low as 100 GeV can induce nonstandard interactions $\varepsilon_{ee}$ as large as $8\%$, potentially hinting at new physics. We also investigate the projected capability of future lepton colliders to probe the currently allowed parameter space consistent with both electron and muon AMMs via direct searches in the $\ell^{+}\ell^{-}\to \ell^{+}\ell^{-}(H \to \ell^{+}\ell^{-})$ channel.