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Title: Theory and phenomenology of an exceptional supersymmetric standard model

Abstract

We make a comprehensive study of the theory and phenomenology of a low-energy supersymmetric standard model originating from a string-inspired E{sub 6} grand unified gauge group. The exceptional supersymmetric standard model (ESSM) considered here is based on the low-energy standard model gauge group together with an extra Z{sup '} corresponding to an extra U(1){sub N} gauge symmetry under which right-handed neutrinos have zero charge. The low-energy matter content of the ESSM corresponds to three 27 representations of the E{sub 6} symmetry group, to ensure anomaly cancellation, plus an additional pair of Higgs-like doublets as required for high-energy gauge coupling unification. The ESSM is therefore a low-energy alternative to the minimal supersymmetric standard model (MSSM) or next-to-minimal supersymmetric standard model (NMSSM). The ESSM involves extra matter beyond the MSSM contained in three 5+5* representations of SU(5), plus three SU(5) singlets which carry U(1){sub N} charges, one of which develops a vacuum expectation value, providing the effective {mu} term for the Higgs doublets, as well as the necessary exotic fermion masses. We explore the renormalization group flow of the ESSM and examine theoretical restrictions on the values of new Yukawa couplings caused by the validity of perturbation theory up to the grandmore » unification scale. We then discuss electroweak symmetry breaking and Higgs phenomenology and establish an upper limit on the mass of the lightest Higgs particle which can be significantly heavier than in the MSSM and NMSSM, in leading two-loop approximation. We also discuss the phenomenology of the Z{sup '} and the extra matter, whose discovery will provide a smoking gun signal of the model.« less

Authors:
; ;  [1]
  1. School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom)
Publication Date:
OSTI Identifier:
20776688
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevD.73.035009; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; APPROXIMATIONS; COUPLING; EXPECTATION VALUE; GAUGE INVARIANCE; HIGGS BOSONS; HIGGS MODEL; NEUTRINOS; PERTURBATION THEORY; RENORMALIZATION; REST MASS; STANDARD MODEL; SU-5 GROUPS; SUPERSYMMETRY; SYMMETRY BREAKING; UNITARY SYMMETRY

Citation Formats

King, S.F., Moretti, S., and Nevzorov, R. Theory and phenomenology of an exceptional supersymmetric standard model. United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.035009.
King, S.F., Moretti, S., & Nevzorov, R. Theory and phenomenology of an exceptional supersymmetric standard model. United States. doi:10.1103/PhysRevD.73.035009.
King, S.F., Moretti, S., and Nevzorov, R. Wed . "Theory and phenomenology of an exceptional supersymmetric standard model". United States. doi:10.1103/PhysRevD.73.035009.
@article{osti_20776688,
title = {Theory and phenomenology of an exceptional supersymmetric standard model},
author = {King, S.F. and Moretti, S. and Nevzorov, R.},
abstractNote = {We make a comprehensive study of the theory and phenomenology of a low-energy supersymmetric standard model originating from a string-inspired E{sub 6} grand unified gauge group. The exceptional supersymmetric standard model (ESSM) considered here is based on the low-energy standard model gauge group together with an extra Z{sup '} corresponding to an extra U(1){sub N} gauge symmetry under which right-handed neutrinos have zero charge. The low-energy matter content of the ESSM corresponds to three 27 representations of the E{sub 6} symmetry group, to ensure anomaly cancellation, plus an additional pair of Higgs-like doublets as required for high-energy gauge coupling unification. The ESSM is therefore a low-energy alternative to the minimal supersymmetric standard model (MSSM) or next-to-minimal supersymmetric standard model (NMSSM). The ESSM involves extra matter beyond the MSSM contained in three 5+5* representations of SU(5), plus three SU(5) singlets which carry U(1){sub N} charges, one of which develops a vacuum expectation value, providing the effective {mu} term for the Higgs doublets, as well as the necessary exotic fermion masses. We explore the renormalization group flow of the ESSM and examine theoretical restrictions on the values of new Yukawa couplings caused by the validity of perturbation theory up to the grand unification scale. We then discuss electroweak symmetry breaking and Higgs phenomenology and establish an upper limit on the mass of the lightest Higgs particle which can be significantly heavier than in the MSSM and NMSSM, in leading two-loop approximation. We also discuss the phenomenology of the Z{sup '} and the extra matter, whose discovery will provide a smoking gun signal of the model.},
doi = {10.1103/PhysRevD.73.035009},
journal = {Physical Review. D, Particles Fields},
number = 3,
volume = 73,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2006},
month = {Wed Feb 01 00:00:00 EST 2006}
}
  • We propose and study a constrained version of the exceptional supersymmetric standard model (E{sub 6}SSM), which we call the cE{sub 6}SSM, based on a universal high energy scalar mass m{sub 0}, trilinear scalar coupling A{sub 0} and gaugino mass M{sub 1/2}. We derive the renormalization group (RG) Equations for the cE{sub 6}SSM, including the extra U(1){sub N} gauge factor and the low-energy matter content involving three 27 representations of E{sub 6}. We perform a numerical RG analysis for the cE{sub 6}SSM, imposing the usual low-energy experimental constraints and successful electroweak symmetry breaking. Our analysis reveals that the sparticle spectrum ofmore » the cE{sub 6}SSM involves a light gluino, two light neutralinos, and a light chargino. Furthermore, although the squarks, sleptons, and Z{sup '} boson are typically heavy, the exotic quarks and squarks can also be relatively light. We finally specify a set of benchmark points, which correspond to particle spectra, production modes, and decay patterns peculiar to the cE{sub 6}SSM, altogether leading to spectacular new physics signals at the Large Hadron Collider.« less
  • The Exceptional Supersymmetric Standard Model (E{sub 6}SSM) provides a low energy alternative to the MSSM, with an extra gauged U(1){sub N} symmetry, solving the mu-problem of the MSSM. Inspired by the possible embedding into an E{sub 6} GUT, the matter content fills three generations of E{sub 6} multiplets, thus predicting exciting exotic matter such as diquarks or leptoquarks. We present predictions from a constrained version of the model (cE{sub 6}SSM), with a universal scalar mass m{sub 0}, trilinear mass A and gaugino mass M{sub 1/2}. We reveal a large volume of the cE{sub 6}SSM parameter space where the correct breakdownmore » of the gauge symmetry is achieved and all experimental constraints satisfied. We predict a hierarchical particle spectrum with heavy scalars and light gauginos, while the new exotic matter can be light or heavy depending on parameters. We present representative cE{sub 6}SSM scenarios, demonstrating that there could be light exotic particles, like leptoquarks and a U(1){sub N} Z' boson, with spectacular signals at the LHC.« less
  • The Exceptional Supersymmetric (SUSY) Standard Model (E{sub 6}SSM) predicts three families of Higgs doublets plus three Higgs singlets, where one family develops vacuum expectation values (VEVs), while the remaining two which do not are called Inert. The model can account for the dark matter relic abundance if the two lightest Inert neutralinos, identified as the (next-to) lightest SUSY particles ((N)LSPs), have masses close to half the Z mass. In this case we find that the usual SM-like Higgs boson decays more than 95% of the time into either LSPs or NLSPs. The latter case produces a final state containing twomore » leptons l{sup +}l{sup -} with an invariant mass less than or about 10 GeV. We illustrate this scenario with a set of benchmark points satisfying phenomenological constraints and the WMAP dark matter relic abundance. This scenario also predicts other light Inert chargino and neutralino states below 200 GeV, and large LSP direct detection cross sections close to current limits and observable soon at XENON100.« less
  • We study electroweak baryogenesis in the E{sub 6} inspired exceptional supersymmetric standard model (E{sub 6}SSM). The relaxation coefficients driven by singlinos and the new gaugino as well as the transport equation of the Higgs supermultiplet number density in the E{sub 6}SSM are calculated. Our numerical simulation shows that both CP-violating source terms from singlinos and the new gaugino can solely give rise to a correct baryon asymmetry of the Universe via the electroweak baryogenesis mechanism.
  • We study electroweak baryogenesis in the E{sub 6} inspired exceptional supersymmetric standard model (E{sub 6}SSM). The relaxation coefficients driven by singlinos and the new gaugino as well as the transport equation of the Higgs supermultiplet number density in the E{sub 6}SSM are calculated. Our numerical simulation shows that both CP-violating source terms from singlinos and the new gaugino can solely give rise to a correct baryon asymmetry of the Universe via the electroweak baryogenesis mechanism.