# Influence of an inert charged Higgs boson on the muon $g-2$ and radiative neutrino masses in a scotogenic model

## TL;DR

This paper explores how adding an inert charged Higgs boson to a scotogenic model can simultaneously explain neutrino masses and the muon g-2 anomaly, with predictions testable at Fermilab and Belle II.

## Contribution

It introduces a minimal extension with a vector-like lepton doublet to address neutrino data and muon g-2 within experimental constraints.

## Key findings

- Muon g-2 can reach ~10^{-9} within the model.
- Predicted tau to mu gamma decay rate matches Belle II sensitivity.
- Model satisfies electroweak and lepton-flavor violation constraints.

## Abstract

A simple extension of Ma's approach in a scotogenic model is studied for the purpose of simultaneously interpreting the neutrino data and the excess of muon anomalous magnetic moment (muon $g-2$). The feasible minimal extension is to add an $Z_2$-odd vector-like lepton doublet to the Ma's model. It is found that in addition to the neutrino data, the strict constraints on the relevant parameters are from the electroweak oblique parameters and the induced lepton-flavor violation processes, such as $\ell_i \to \ell_j \gamma$ and $\ell_i \to \ell^-_j \ell^-_j \ell^+_j$. Performing parameter scan, we numerically demonstrate that when the constraint conditions are satisfied, the muon $g-2$ of $O(10^{-9})$ can be achieved, where it can be expected that with a $5\sigma$ observation, the Muon $g-2$ experiment at Fermilab can observe $a_\mu \approx 13.31 \times 10^{-10}$ when the current experiment and the SM errors are reduced by a factor of 4 and 2, respectively. Moreover, the branching ratio of the $\tau \to \mu \gamma$ decay can match the Belle II sensitivity of $O(10^{-9})$ with an integrated luminosity of 50 ab$^{-1}$.