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Supergravity grand unification, proton decay and cosmological constraints

Description: Properties and experimental predictions of a broad class of supergravity grand unified models possessing an SU(5)-type proton decay and R parity are described. Models of this type can be described in terms of four parameters at the Gut scale in addition to those of the Standard Model i.e. m{sub 0} (universal scalar mass), m{sub 1/2} (universal gaugino mass), A{sub 0} (cubic soft breaking parameter) and tan {beta} = <H{sub 2}>/<H{sub 1}>. Thus the 32 SUSY masses can be expressed in terms of m{sub 0}, M{sub 1/2}, A{sub 0} tan {beta} and the as yet unknown t-quark mass M{sub t}. Gut thresholds are examined and a simple model leads to grand unification consistent with p-decay data when 0.114 < {alpha}{sub 3}(M{sub z}) < 0.135, in agreement with current values of {alpha}{sub 3}(M{sub Z}). Proton decay is examined for the superheavy Higgs triplet mass H{sub H3} < 10M{sub G}(M{sub G} {approx_equal} 1.5 {times} 10{sup 16} GeV) and squarks and gluinos lighter than 1 TeV. Throughout most of the parameter space chargino-neutralino scaling relations are predicted to hold: 2m{sub {anti Z}}{sub 1} {congruent} m{sub {anti W}}{sub 1} {congruent} m{sub {anti Z}}{sub 2}, m{sub {anti W}}{sub 1} {approx_equal} (1/4)m{sub {anti g}} (for {mu} > 0) or m{sub {anti W}}{sub 1} {approx_equal} (1/3)m{sub {anti g}} (for {mu} < 0), while m{sub {anti W}}{sub 2} {congruent} m{sub {anti Z}}{sub 3} {congruent} m{sub {anti Z}}{sub 4} {much_gt} m{sub {anti Z}}{sub 1}. Future proton decay experiments combined with LEP2 lead to further predictions, e.g. for the entire parameter space either proton decay should be seen at these or the {anti W}{sub 1} seen at LEP2. Relic density constraints on the {anti Z}{sub 1} further constrain the parameter space e.g. so that m{sub t} < 165 GeV, M{sub h} < 105 GeV, m{sub {anti W}}{sub 1} < 100 GeV ...
Date: May 1, 1995
Creator: Arnowitt, R. & Nath, P.
Partner: UNT Libraries Government Documents Department

Supersymmetry and supergravity: Phenomenology and grand unification

Description: A survey is given of supersymmetry and supergravity and their phenomenology. Some of the topics discussed are the basic ideas of global supersymmetry, the minimal supersymmetric Standard Model (MSSM) and its phenomenology, the basic ideas of local supersymmetry (supergravity), grand unification, supersymmetry breaking in supergravity grand unified models, radiative breaking of SU(2) {times} U(1), proton decay, cosmological constraints, and predictions of supergravity grand unified models. While the number of detailed derivations are necessarily limited, a sufficient number of results are given so that a reader can get a working knowledge of this field.
Date: December 31, 1993
Creator: Arnowitt, R. & Nath, P.
Partner: UNT Libraries Government Documents Department

Supersymmetry Parameter Analysis: SPA Convention andProject

Description: High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e{sup +}e{sup -} linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.
Date: December 2, 2005
Creator: Aguilar-Saavedra, J.A.; Ali, A.; Allanach, B.C.; Arnowitt, R.; Baer, H.A.; Bagger, J.A. et al.
Partner: UNT Libraries Government Documents Department