Natural Two-Higgs-Doublet Model

TL;DR

This paper demonstrates that a Two-Higgs-Doublet Model, constrained by two-loop divergence cancellation, aligns with experimental data and alleviates the little hierarchy problem by raising the natural cutoff scale.

Contribution

It introduces a 2HDM framework constrained at two-loop order that addresses the hierarchy problem and predicts enhanced CP violation effects.

Findings

Quadratic divergences are canceled at two-loop order in the model.

The model raises the natural cutoff scale from 0.6 TeV to over 6 TeV.

The model predicts a strong source of CP violation.

Abstract

We show that the Two-Higgs-Doublet Model (2HDM) constrained by the two-loop-order requirement of cancellation of quadratic divergences is consistent with the existing experimental constraints. The model allows to ameliorate the little hierarchy problem by suppressing the quadratic corrections to scalar masses and lifting the mass of the lightest Higgs boson. A strong source of CP violation emerges from the scalar potential. The cutoff originating from the naturality arguments is shifted from 0.6 TeV in the Standard Model to >6 TeV in the 2HDM, depending on the mass of the lightest scalar.