Testing aligned CP-violating Higgs sector at future lepton colliders

TL;DR

This paper explores how future lepton colliders can test CP-violating phases in an aligned two Higgs doublet model, using tau decay azimuthal distributions to distinguish CP violation from conservation.

Contribution

It demonstrates the potential to detect CP-violating phases in a specific aligned two Higgs doublet model at future lepton colliders through tau decay analysis.

Findings

CP-violating phases can be distinguished from CP-conserving scenarios.

Azimuthal angle distributions of tau decays carry information about CP violation.

Future colliders like the ILC can test these CP-violating effects.

Abstract

We discuss the testability of CP-violating phases at future lepton colliders for the scenario which satisfies electric dipole moment data by destructive interferences among several phases. We consider the general but aligned two Higgs doublet model which has the CP-violating phases in the Higgs potential and the Yukawa interaction. The Yukawa interaction terms are aligned to avoid flavor changing neutral currents at tree level. The Higgs potential is also aligned such that the coupling constants of the lightest Higgs boson with the mass of 125 GeV to the Standard Model (SM) particles are the same as those of the SM at tree level. We investigate the azimuthal angle distribution of the hadronic decay of tau leptons arising from production and decay of the extra Higgs bosons, which contains information of the CP-violating phases. From the signal and background simulation, we find that the scenario with finite CP-violating phases can be distinguished from CP conserving one at future lepton colliders like the International Linear Collider.