Confronting Higgs couplings from D-term extensions and Natural SUSY at the LHC and ILC

TL;DR

This paper investigates how non-decoupling D-term extensions of the MSSM can modify Higgs couplings, potentially easing fine-tuning and allowing lighter stops, and assesses the LHC and ILC's ability to detect these deviations.

Contribution

It analyzes various non-decoupling D-term MSSM extensions and evaluates the potential of LHC and ILC to distinguish their Higgs coupling deviations from the Standard Model.

Findings

Deviations in Higgs couplings depend on the heavier Higgs mass.

ILC can determine deviations at different energy stages.

LHC constraints vary with model parameters.

Abstract

Non-decoupling D-term extensions of the MSSM enhance the tree-level Higgs mass compared to the MSSM, therefore relax fine-tuning and may allow lighter stops with rather low masses even without maximal mixing. We present the anatomy of various non-decoupling D-term extensions of the MSSM and explore the potential of the LHC and of the International Linear Collider (ILC) to determine their deviations in the Higgs couplings with respect to the Standard Model. Depending on the mass of the heavier Higgs $m_H$, such deviations may be constrained at the LHC and determined at the ILC. We evaluate the Higgs couplings in different models and study the prospects for a model distinction at the different stages of the ILC at $\sqrt{s}=$250, 500, 1000 GeV, including the full luminosity upgrade and compare it with the prospects at HL-LHC.