From Higgs physics to lepton flavour violation: current bounds and future prospects for vector-like lepton models

TL;DR

This paper thoroughly examines six vector-like lepton models, analyzing their implications for Higgs and lepton physics, and assesses their testability with current and future collider and precision experiments.

Contribution

It provides the first comprehensive phenomenological analysis of these models, highlighting their distinctive signatures and correlations across multiple observables.

Findings

Models predict observable lepton flavour violation signals.

Correlations between collider and low-energy measurements are identified.

Parameter space is constrained by recent LHC and muon g-2 results.

Abstract

We present a comprehensive phenomenological study of a class of six vector-like lepton models with seesaw-like mass contributions and strong modifications to Higgs and lepton phenomenology. We focus on lepton flavour conserving and violating observables across all lepton generations and collider observables like $Z$ and Higgs decays. In light of the recent progress at the LHC and precision measurements such as muon $g-2$, as well as in anticipation of upcoming experiments like MEGII, Mu2e/COMET, Mu3e, Belle II and at the HL-LHC, we systematically survey the viable parameter space and identify patterns and correlations. The considered class of models gives rise to a rich and testable phenomenology with robust and complementary probes that allow to distinguish between models in the coming experimental era.