Measuring the triple Higgs self-couplings in two Higgs doublet model

TL;DR

This paper analyzes how to measure the additional Higgs self-couplings in the two-Higgs-doublet model at future lepton colliders, providing numerical results and strategies for experimental extraction.

Contribution

It offers a detailed numerical analysis of Higgs self-couplings in the 2HDM and proposes strategies for their measurement at future colliders.

Findings

Cross section distributions depend on beam polarization.

Measurement strategies are developed for different Higgs final states.

Analysis is performed at the exact alignment limit up to 3 TeV.

Abstract

The determination of the Higgs self-coupling in the Standard Model is one of the primary motivations among all the future lepton colliders. Extending the scalar sector of the Standard Model by a new Higgs doublet with a quadratic Higgs potential gives many new features to the model, and most importantly additional Higgs self-couplings emerge. Measuring these couplings is the only way to reconstruct the shape of the scalar potential. In this study, the numerical analysis of several scattering processes is carried out for the two-Higgs-doublet model to determine all these Higgs self-couplings. These processes are selected among various possible combinations of additional Higgs states. The computation is carried out in the exact alignment limit ($s_{\beta\alpha}=1$). The distribution of the cross sections is presented regarding the polarization of the incoming beams and up to $\sqrt{s}=3\text{ TeV}$. A strategy for extracting the Higgs self-couplings are considered in 2HDM and at the future lepton colliders. Possible final states that could be used for each of the processes are investigated using the decays of the final state particles.