[Paper Review] Search for SUSY and Higgs particles

W. De Boer|arXiv (Cornell University)|Aug 28, 1998

Particle physics theoretical and experimental studies3 citations

TL;DR

This paper reviews experimental and theoretical constraints on supersymmetry (SUSY) and Higgs bosons as of 1998, focusing on the Minimal Supersymmetric Standard Model (MSSM). It synthesizes results from the $sg$ decay rate, direct Higgs searches (with limits near 90 GeV), and cosmological observations to significantly constrain the MSSM parameter space, highlighting the growing tension between theory and experimental data at the time.

ABSTRACT

An overview of hints for new physics outside the Standard Model and the status of sparticle and Higgs searches is given. The present limits on Higgs bosons of about 90 GeV as well as the $\bsg$ rate and cosmological constraints severely restrict the available parameter space of the MSSM.

Motivation & Objective

• To assess the status of experimental searches for supersymmetric (SUSY) particles and Higgs bosons as of 1998.
• To evaluate the impact of existing constraints—particularly from the $B \to s\gamma$ decay rate, direct Higgs searches, and cosmological observations—on the viable parameter space of the MSSM.
• To provide a comprehensive phenomenological overview of the MSSM in light of the latest experimental data available at the time.
• To identify the most stringent limits on SUSY and Higgs sectors, guiding future experimental and theoretical efforts.

Proposed method

• The paper compiles and analyzes experimental results from high-energy colliders, including direct searches for sparticles and Higgs bosons.
• It incorporates constraints from the measured $B \to s\gamma$ decay rate, which is sensitive to chargino and charged Higgs contributions in the MSSM.
• Cosmological constraints, such as those from dark matter relic density, are applied to restrict the allowed parameter space of the MSSM.
• The analysis uses theoretical frameworks of the MSSM to interpret experimental limits, particularly focusing on the Higgs sector and R-parity conserving scenarios.
• The study integrates results from the 1998 XVIII Physics in Collision Conference, including updated data from LEP and other experiments.
• It presents graphical and numerical summaries of the allowed regions in the MSSM parameter space, using 10 EPS figures to illustrate constraints.

Experimental results

Research questions

• RQ1 What are the current experimental limits on the mass of the Higgs boson in the context of the MSSM, particularly around 90 GeV?
• RQ2 How do the measured $B \to s\gamma$ decay rates constrain the parameter space of the MSSM?
• RQ3 To what extent do cosmological observations, such as the relic density of dark matter, restrict the viable parameter space of the MSSM?
• RQ4 How do direct searches for sparticles at colliders constrain the masses and couplings of supersymmetric particles?
• RQ5 What is the combined impact of all these constraints on the overall viability of the MSSM as a theory beyond the Standard Model?

Key findings

• The Higgs boson mass is constrained to be below approximately 90 GeV by direct experimental searches, with no discovery reported.
• The measured $B \to s\gamma$ decay rate places strong constraints on the chargino and charged Higgs masses, particularly in the context of the MSSM.
• Cosmological constraints, especially from the relic density of weakly interacting massive particles (WIMPs), further restrict the allowed parameter space of the MSSM.
• The combination of $B \to s\gamma$, Higgs limits, and cosmological data significantly reduces the viable region of the MSSM parameter space.
• The paper concludes that the MSSM is under increasing pressure from experimental data, with only narrow regions of parameter space remaining consistent with all constraints.
• The results highlight the urgency for future experiments, such as those at the Tevatron and LHC, to either discover SUSY or rule out the model definitively.