Dark Two Higgs Doublet Model

TL;DR

This paper investigates a Two Higgs Doublet Model with a light gauge boson Z' that could explain astrophysical anomalies and muon g-2 deviations, analyzing experimental constraints and proposing new LHC search channels.

Contribution

It introduces a specific 2HDM with a U(1) gauge symmetry and a light Z', exploring its phenomenology and experimental signatures.

Findings

Constraints from current experiments on the model parameters.

Predictions of novel Higgs decay channels involving lepton-jets.

Potential explanations for astrophysical anomalies and muon g-2 deviations.

Abstract

We perform a detailed study of a specific Two Higgs Doublet Model (2HDM) with a U(1) gauge symmetry, instead of a typical Z2 discrete symmetry, containing a very light gauge boson Z' (GeV scale or below). The Standard Model (SM) fermions do not carry U(1) charges, but induced couplings to the Z' (called the dark Z) are generated through mixing with the SM neutral gauge bosons. Such a light Z' could explain some astrophysical anomalies as well as the muon g-2 deviation, and has been the subject of great experimental interest. We consider the scenario in which the 125 GeV SM-like Higgs (H) is the heavier scalar state, and focus on the lighter neutral state (h) as well as charged Higgs. We analyze the constraints on the model from various experiments and predict novel channels to search for these Higgs scalars at the LHC. In particular, experiments looking for lepton-jets are among potentially important searches.