Explaining $g-2$ anomalies in two Higgs doublet model with vector-like leptons

TL;DR

This paper proposes a two Higgs doublet model with vector-like leptons to explain the discrepancies in electron and muon magnetic moments, highlighting a light pseudo-scalar's role in reconciling experimental observations.

Contribution

It introduces a novel combination of 2HDM and vector-like leptons to simultaneously address electron and muon g-2 anomalies, with detailed analysis of the pseudo-scalar's effects.

Findings

Light pseudo-scalar explains muon g-2 at two-loop

Vector-like leptons induce negative electron g-2 contribution

Model evades current experimental constraints

Abstract

We consider the two Higgs doublet model (2HDM) along with a generation of vector-like lepton doublet and singlet to explain the observed discrepancies in the electron and muon anomalous magnetic moments. The type-X (lepton-specific) 2HDM can allow a light pseudo-scalar which is known to explain the muon anomalous magnetic moment at two-loop. Such a light particle induces a sizable negative contribution to the electron anomalous magnetic moment at one-loop in the presence of vector-like leptons evading all the experimental constraints.