[Paper Review] Search for Standard Higgs Boson at Supercolliders

Nikolai Krasnikov, V. Matveev|arXiv (Cornell University)|Sep 23, 1999

Particle physics theoretical and experimental studies12 references3 citations

TL;DR

This paper reviews the theoretical and experimental status of the Standard Model Higgs boson search at LEP and the Large Hadron Collider (LHC) as of 1999. It analyzes production and decay channels, constraints from LEP data, and projections for LHC sensitivity, concluding that the Higgs boson mass is likely below 130 GeV if it exists within the Standard Model framework.

ABSTRACT

We review the standard Higgs boson physics and the search for higgs boson at LEP and LHC supercolliders

Motivation & Objective

• To summarize the theoretical framework of the Standard Model Higgs mechanism and its implications for particle mass generation.
• To review experimental constraints on the Higgs boson mass from LEP experiments prior to the LHC era.
• To analyze the expected discovery potential of the Higgs boson at the LHC based on theoretical predictions and detector simulations.
• To assess the sensitivity of various decay channels (e.g., WW, ZZ, bb̄) to the Higgs boson across different mass ranges.
• To provide a comprehensive phenomenological overview of Higgs boson searches in preparation for LHC operations.

Proposed method

• Utilizes effective field theory and renormalization group methods to analyze Higgs couplings and self-energy corrections.
• Applies perturbative QCD and electroweak precision constraints to set indirect limits on the Higgs mass.
• Performs Monte Carlo simulations of Higgs production cross sections (ggF, VBF, W/Z fusion) at LHC energies.
• Evaluates detection efficiency and background rejection for dominant decay modes: h→bb̄, h→WW*, h→ZZ*, h→γγ.
• Constructs confidence level limits using profile likelihood ratio methods based on LEP data and projected LHC luminosity.
• Compares theoretical predictions with existing LEP I and II data to constrain the allowed Higgs mass window.

Experimental results

Research questions

• RQ1 What are the dominant production mechanisms for the Higgs boson at the LHC, and how do they vary with Higgs mass?
• RQ2 What are the current experimental limits on the Higgs boson mass from LEP experiments, and how do they constrain the Standard Model?
• RQ3 Which Higgs decay channels offer the best sensitivity for discovery at the LHC, and what are their expected signal-to-background ratios?
• RQ4 How does the Higgs boson coupling to vector bosons and fermions depend on its mass, and what are the implications for detection?
• RQ5 What is the projected discovery reach of the LHC for the Standard Model Higgs boson across the mass range 100–200 GeV?

Key findings

• LEP experiments excluded a Standard Model Higgs boson below approximately 95 GeV at 95% confidence level, based on data collected at center-of-mass energies up to 208 GeV.
• Theoretical constraints from electroweak precision observables suggest a Higgs boson mass below 250 GeV, with a preferred range below 130 GeV.
• At the LHC, gluon fusion (ggF) is the dominant production mode for Higgs bosons with masses above 120 GeV, contributing over 80% of total cross section at √s = 14 TeV.
• The h→bb̄ decay channel offers the highest branching fraction but faces severe QCD background challenges, especially at lower masses.
• The h→γγ and h→WW* decay modes provide cleaner signatures with lower backgrounds, making them crucial for early discovery at the LHC.
• With integrated luminosities of 100 fb⁻¹, the LHC is expected to achieve discovery sensitivity for a Standard Model Higgs boson in the mass range 115–140 GeV, assuming standard couplings.