New Constraints on Extended Higgs Sectors from the Trilinear Higgs Coupling

Area of Science:

• High Energy Physics
• Particle Physics
• Beyond Standard Model Physics

Background:

• The trilinear Higgs coupling (λhhh) is a fundamental parameter in the Standard Model of particle physics.
• Understanding λhhh is crucial for probing the Higgs potential and searching for new physics beyond the Standard Model.
• Deviations in λhhh can indicate the presence of extended Higgs sectors, such as in Two-Higgs-Doublet Models (2HDMs).

Purpose of the Study:

• To investigate parameter regions in the Two-Higgs-Doublet Model (2HDM) where the trilinear Higgs coupling (λhhh) is significantly enhanced.
• To analyze the impact of two-loop corrections on the constraints of λhhh.
• To determine how current experimental bounds on λhhh can rule out unconstrained parameter space in extended Higgs models.

Main Methods:

• Focusing on the Two-Higgs-Doublet Model (2HDM) as a representative example of an extended Higgs sector.
• Calculating relevant corrections up to the two-loop level for the trilinear Higgs coupling (λhhh).
• Comparing theoretical predictions with current experimental bounds on λhhh.

Main Results:

• Identified specific parameter regions within the 2HDM that lead to a significantly enhanced trilinear Higgs coupling (λhhh) compared to the Standard Model.
• Demonstrated that existing experimental constraints on λhhh already exclude substantial portions of the 2HDM parameter space.
• Illustrated the implications of these results for a benchmark scenario, showing the power of experimental bounds.

Conclusions:

• Current experimental limits on the trilinear Higgs coupling (λhhh) are effective in constraining parameter space in models beyond the Standard Model, particularly the 2HDM.
• The study highlights the importance of precise measurements of λhhh for probing new physics.
• Similar constraints are anticipated for a broad range of models featuring extended Higgs sectors.