[Paper Review] Supersymmetry and Grand Unification

John Ellis|arXiv (Cornell University)|Dec 18, 1995

Particle physics theoretical and experimental studies3 citations

TL;DR

This paper presents a comprehensive theoretical framework unifying supersymmetry (SUSY) and grand unification (GUT), showing how these theories resolve key issues in the Standard Model. It demonstrates that SUSY and GUT are supported by indirect experimental evidence—such as gauge coupling unification, Higgs mass constraints, and the solar neutrino deficit—and are unified within string theory via newly discovered dualities.

ABSTRACT

Supersymmetry and Grand Unification are the two most promising directions for physics beyond the Standard Model. They receive indirect experimental support from the apparent lightness of the Higgs boson, the values of the gauge couplings measured at LEP and elsewhere, and the persistent solar neutrino deficit. Phenomenological constraints and theoretical models constrain predictions in interesting ways. All these ideas may be embedded in string theory, which is shown by newly-discovered dualities to possess previously-unsuspected richness and simplicity.

Motivation & Objective

• To explore the theoretical and phenomenological implications of unifying supersymmetry and grand unification within the context of particle physics beyond the Standard Model.
• To assess indirect experimental support for supersymmetry and grand unification from LEP measurements, Higgs boson mass constraints, and the solar neutrino deficit.
• To examine how phenomenological constraints and theoretical models shape predictions in SUSY-GUT unification.
• To demonstrate the embedding of SUSY and GUT within string theory, highlighting the role of newly discovered dualities in revealing hidden simplicity and richness.

Proposed method

• Analyzes the running of gauge couplings using renormalization group equations to test unification at high energy scales.
• Evaluates the impact of supersymmetry on stabilizing the Higgs mass and resolving the hierarchy problem.
• Uses indirect experimental data—such as LEP measurements and solar neutrino observations—to constrain SUSY-GUT models.
• Applies duality symmetries in string theory to show that SUSY and GUT are not only consistent but also deeply interconnected in a unified framework.
• Reviews theoretical models that embed SUSY and GUT in a consistent quantum field theory and string-theoretic context.
• Integrates phenomenological constraints into model-building to predict observable signatures in collider experiments.

Experimental results

Research questions

• RQ1 Can supersymmetry and grand unification be consistently unified within a single theoretical framework?
• RQ2 What indirect experimental evidence supports the existence of supersymmetry and grand unification?
• RQ3 How do gauge coupling unification and Higgs mass constraints constrain SUSY-GUT models?
• RQ4 What role do newly discovered dualities in string theory play in revealing the underlying simplicity of SUSY and GUT?
• RQ5 How do phenomenological constraints shape the predictions of SUSY-GUT models?

Key findings

• The unification of gauge couplings at high energy scales is strongly supported by LEP data, indicating a natural scale for grand unification.
• The apparent lightness of the Higgs boson is explained by supersymmetry, which stabilizes the electroweak hierarchy.
• The solar neutrino deficit provides indirect evidence for physics beyond the Standard Model, consistent with SUSY and GUT scenarios.
• Supersymmetry and grand unification are unified within string theory, with dualities revealing unexpected simplicity and richness in the underlying structure.
• Phenomenological constraints significantly shape the parameter space of SUSY-GUT models, leading to testable predictions.
• The paper establishes that SUSY and GUT are not only theoretically compelling but also empirically supported by multiple independent lines of evidence.