Off-Shell Higgs Probe of Naturalness

Area of Science:

• High Energy Physics
• Particle Physics
• Cosmology

Background:

• The naturalness problem of the Higgs boson mass remains a key challenge in particle physics.
• Off-shell Higgs production offers a unique window into physics at high energy scales.

Purpose of the Study:

• To explore the potential of off-shell Higgs production at the LHC to probe new physics.
• To investigate a specific model featuring a new scalar field coupled to the Standard Model Higgs.
• To address the naturalness problem of the Higgs boson mass.

Main Methods:

• Utilizing a representative model with a new scalar field (S) coupled to the Standard Model Higgs doublet (H) via a |S|^{2}|H|^{2} interaction.
• Analyzing the process pp→h^{*}→ZZ at the Large Hadron Collider (LHC).
• Examining one-loop scalar singlet corrections to the differential distribution of the Z-pair invariant mass.

Main Results:

• A measurable deviation in the Z-pair invariant mass distribution is predicted above the 2m_{S} threshold.
• The proposed new physics can be probed at the 5σ significance level at the High-Luminosity LHC.
• The sensitivity improves with an upgraded 27 TeV LHC.

Conclusions:

• The study demonstrates the feasibility of detecting new physics through off-shell Higgs production without precise Higgs width measurements.
• Discovery of such a Higgs portal could have significant implications for thermal dark matter and electroweak baryogenesis.