Highly enhanced contributions of heavy Higgs bosons and new leptons to muon $g-2$ and prospects at future colliders

TL;DR

This paper proposes a two Higgs doublet model with vectorlike leptons that explains the muon g-2 anomaly through enhanced contributions from heavy Higgs bosons and leptons, with testable predictions at future colliders.

Contribution

It introduces a novel model combining two Higgs doublets and vectorlike leptons, achieving significant muon g-2 contributions compatible with current measurements.

Findings

Muon g-2 explained with TeV-scale leptons and Higgs bosons.

Model remains perturbative up to high energy scales.

Future colliders can fully probe this scenario.

Abstract

We show that in a two Higgs doublet model type-II extended by vectorlike leptons the contributions from heavy neutral and charged Higgs bosons to the anomalous magnetic moment of the muon simultaneously feature chiral enhancement from masses of new leptons and $\tan^2 \beta$ enhancement from couplings of Higgs bosons. Assuming moderate values of new Yukawa couplings, not exceeding one, that can remain perturbative to very high energy scales, the measured value of muon $g-2$ can be explained within one standard deviation even with 6.5 TeV leptons or 20 TeV Higgs bosons. Allowing new couplings near the perturbativity limit, these mass ranges extend to 45 TeV for leptons and 190 TeV for Higgs bosons. In spite of the high scale of new physics this scenario can be completely probed at planned future colliders.