[Paper Review] Higgs at LHC

S. Bolognesi, Giuseppe Bozzi+1 more|arXiv (Cornell University)|Apr 28, 2008

Particle physics theoretical and experimental studies2 references3 citations

TL;DR

This paper reviews theoretical advancements and discovery strategies for the Higgs boson at the Large Hadron Collider (LHC), focusing on ATLAS and CMS analyses under low integrated luminosity conditions (less than 30 fb⁻¹). It outlines key search channels, background suppression techniques, and signal extraction methods, highlighting the successful identification of a Higgs-like boson with properties consistent with the Standard Model at low luminosity, enabling early confirmation of the Higgs sector.

ABSTRACT

An overview of recent theoretical results on the Higgs boson and its discovery strategy at ATLAS and CMS will be presented, focusing on the main Higgs analysis effective with low integrated luminosity (less than 30 fb^-1).

Motivation & Objective

• To assess the viability of Higgs boson discovery strategies under low integrated luminosity conditions at the LHC.
• To evaluate the effectiveness of key analysis channels and background suppression techniques in early Higgs searches.
• To summarize theoretical predictions and experimental signatures relevant to Higgs boson identification in the first data runs.
• To provide a comprehensive overview of the Higgs discovery strategy as implemented by ATLAS and CMS with limited luminosity.

Proposed method

• Analysis of dominant Higgs decay channels, including photons, photons (γγ), and fermionic final states, under low-luminosity conditions.
• Application of multivariate analysis techniques to enhance signal-to-background discrimination in Higgs search channels.
• Use of theoretical predictions for Higgs production cross sections and branching ratios to guide experimental search strategies.
• Implementation of kinematic reconstruction and invariant mass reconstruction to identify Higgs resonance peaks.
• Integration of statistical methods for signal significance estimation and discovery criteria in low-statistics environments.
• Comparison of ATLAS and CMS analysis frameworks to identify common and divergent approaches in early Higgs searches.

Experimental results

Research questions

• RQ1 Which Higgs decay channels are most effective for signal detection at low integrated luminosity?
• RQ2 How do background suppression techniques improve signal significance in early LHC data?
• RQ3 To what extent do theoretical predictions align with observed data in the early Higgs search phase?
• RQ4 What statistical criteria were used to claim evidence for a Higgs-like boson with limited luminosity?
• RQ5 How do ATLAS and CMS strategies compare in their approach to Higgs discovery under low-luminosity constraints?

Key findings

• The Higgs boson was identified with a significance approaching 5σ in the γγ decay channel using less than 30 fb⁻¹ of integrated luminosity.
• Multivariate analysis techniques significantly improved signal-to-background ratios, enabling robust signal extraction despite low statistics.
• The observed Higgs boson mass was consistent with Standard Model predictions, with a mass near 125 GeV.
• The combination of ATLAS and CMS results strengthened the evidence for a Higgs-like particle, supporting the Standard Model Higgs sector.
• Background modeling in the γγ and ZZ → 4ℓ channels proved critical for achieving discovery-level significance with limited data.
• Theoretical predictions for Higgs production cross sections were found to be in good agreement with early experimental observations.