Charged Lepton EDM with Extra Yukawa Couplings

TL;DR

This paper explores how extra Yukawa couplings in a two Higgs doublet model can significantly enhance charged lepton EDMs, especially muon and tau, potentially observable in upcoming experiments, and links these effects to the muon g-2 anomaly.

Contribution

It introduces a detailed analysis of charged lepton EDMs within a two Higgs doublet model with extra Yukawa couplings, highlighting potential experimental signatures and their relation to the muon g-2 anomaly.

Findings

Muon and tau EDMs can be larger than in standard new physics models.

Flavor-conserving top coupling $ ho_{tt}$ dominates two-loop contributions.

Large muon EDMs can be induced by lepton flavor violating couplings if muon g-2 anomaly is explained.

Abstract

In a two Higgs doublet model with extra Yukawa couplings, we assess the new physics contributions to charged lepton electric dipole moment. We focus especially on muon (and tau) EDM where in the coming decade several experiments $-$ Muon g-2, J-PARC and PSI (and Belle II) $-$ will push sensitivities down by several orders of magnitude. With the working assumption that extra Yukawa couplings are analogous to SM ones in strength and taking exotic scalar masses in sub-TeV range, we find that $\mu$ and $\tau$ EDM can be enhanced to values larger than new physics scenarios that scale with lepton mass. The main effect comes from the flavor-conserving extra top coupling $\rho_{tt}$ via well-known two-loop diagrams. Deviating from our working assumption, if the muon $g-2$ anomaly arises from the one-loop diagram, driven by singly enhanced lepton flavor violating $\rho_{\tau\mu}$ coupling, it can also induce rather large muon EDM, accessible at upcoming experiments.