The Higgs Portal from LHC to ILC

TL;DR

This paper explores how mixing between the Higgs boson and a hidden sector affects Higgs search results at the LHC and ILC, emphasizing the importance of measuring invisible decays to identify potential deviations from the Standard Model.

Contribution

It introduces a model of Higgs-hidden sector mixing and discusses how future colliders can help detect invisible decay modes to confirm such scenarios.

Findings

LHC bounds can be interpreted in terms of Higgs-hidden mixing

Invisible decays are crucial for identifying deviations from the Standard Model

Future linear colliders are essential for precise measurements of invisible Higgs decays

Abstract

Interpretations of searches for the Higgs boson are governed by model-dependent combinations of Higgs production cross sections and Higgs branching ratios. Mixing of the Higgs doublet with a hidden sector captures modifications from the Standard Model Higgs phenomenology in the standard search channels in a representative way, in particular because invisible Higgs decay modes open up. As a consequence, LHC exclusion bounds, which disfavor a heavy Standard Model Higgs can be consistently understood in terms of a standard-hidden mixed Higgs system. Shedding light on the possible existence of such an admixture with a hidden sector and quantifying the resemblance of an eventually discovered scalar resonance with the Standard Model Higgs crucially depends on measurement of invisible decays. This task will already be tackled at LHC, but eventually requires the clean environment of a future linear collider to be ultimately completed.