Grand Unified Theories and Supersymmetry in Particle Physics and Cosmology

Abstract

A review is given on the consistency checks of Grand Unified Theories (GUT), which unify the electroweak and strong nuclear forces into a single theory. Such theories predict a new kind of force, which could provide answers to several open questions in cosmology. The possible role of such a “primeval” force will be discussed in the framework of the Big Bang Theory. Although such a force cannot be observed directly, there are several predictions of GUT’s, which can be verified at low energies. The Minimal Supersymmetric Standard Model (MSSM) distinguishes itself from other GUT’s by a successful prediction of many unrelated phenomena with a minimum number of parameters. Among them: a) Unification of the couplings constants; b) Unification of the masses; c) Existence of dark matter; d) Proton decay; e) Electroweak symmetry breaking at a scale far below the unification scale. A fit of the free parameters in the MSSM to these low energy constraints predicts the masses of the as yet unobserved superpartners of the SM particles, constrains the unknown top mass to a range between 140 and 200 GeV, and requires the second order QCD coupling constant to be between 0.108 and 0.132. (Published in “Progress in Particle and Nuclear Physics, 33 (1994) 201”.) Email: Wim.de.Boer@cern.ch Based on lectures at the Herbstschule Maria Laach, Maria Laach (1992) and the HeisenbergLandau Summerschool, Dubna (1992). “The possibility that the universe was generated from nothing is very interesting and should be further studied. A most perplexing question relating to the singularity is this: what preceded the genesis of the universe? This question appears to be absolutely methaphysical, but our experience with metaphysics tells us that metaphysical questions are sometimes given answers by physics.” A. Linde (1982)

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Cite this paper

@inproceedings{Boer1994GrandUT, title={Grand Unified Theories and Supersymmetry in Particle Physics and Cosmology}, author={Wim de Boer}, year={1994} }