Probing New Physics in the Vector-like Lepton Model by Lepton Electric Dipole Moments

TL;DR

This paper explores how a vector-like lepton extension of the Standard Model can simultaneously address the muon g-2 anomaly and predict sizable electron and muon electric dipole moments, which are testable in future experiments.

Contribution

It introduces a model with vector-like leptons that couple to second-generation leptons, explaining muon g-2 and predicting measurable EDMs at two-loop level.

Findings

The model can explain the muon g-2 anomaly.

Predicted EDMs are within reach of future experiments.

Parameter regions are consistent with current constraints.

Abstract

We examine the lepton dipole moments in an extension of the Standard Model (SM), which contains vector-like leptons that couple only to the second-generation SM leptons. The model naturally leads to sizable contributions to the muon $g-2$ and the muon electric dipole moment (EDM). One feature of this model is that a sizable electron EDM is also induced at the two-loop level due to the existence of new vector-like leptons in the loops. We find parameter regions that can explain the muon $g-2$ anomaly and are also consistent with the experimental constraints coming from the electron EDM and the Higgs decay $h\rightarrow \mu^{+}\mu^{-}$. The generated EDMs can be as large as $O(10^{-22})~e \cdot \mathrm{cm}$ for the muon and $O(10^{-30})~e \cdot \mathrm{cm}$ for the electron, respectively, which can be probed in future experiments for the EDM measurements.