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Title: Dimension-five operators in grand unified theories

Abstract

Extensions of the standard model with low-energy supersymmetry generically allow baryon- and lepton-number violating operators of dimension four and five, yielding rapid proton decay. The dimension-four operators are usually forbidden by matter parity. We investigate to what extent the appearance of dimension-five operators at the Planck scale may be constrained by the different grand-unified gauge groups. Dimension-five operators are suppressed in models based on E{sub 6} and SU(3){sub C}xSU(3){sub L}xSU(3){sub R}, where four matter fields do not form a gauge singlet. An intermediate scale offers the possibility to sufficiently suppress these dimension-five operators.

Authors:
; ;  [1]
  1. Department of Physics, University of Illinois at Urbana-Champaign 1110 West Green Street, Urbana, Illinois 61801 (United States)
Publication Date:
OSTI Identifier:
21011026
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevD.75.037702; (c) 2007 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; FIELD OPERATORS; LEPTON NUMBER; MANY-DIMENSIONAL CALCULATIONS; PARITY; PROTONS; STANDARD MODEL; SU-3 GROUPS; SUPERSYMMETRY; SYMMETRY BREAKING

Citation Formats

Sayre, Joshua, Wiesenfeldt, Soeren, and Willenbrock, Scott. Dimension-five operators in grand unified theories. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.037702.
Sayre, Joshua, Wiesenfeldt, Soeren, & Willenbrock, Scott. Dimension-five operators in grand unified theories. United States. doi:10.1103/PHYSREVD.75.037702.
Sayre, Joshua, Wiesenfeldt, Soeren, and Willenbrock, Scott. Thu . "Dimension-five operators in grand unified theories". United States. doi:10.1103/PHYSREVD.75.037702.
@article{osti_21011026,
title = {Dimension-five operators in grand unified theories},
author = {Sayre, Joshua and Wiesenfeldt, Soeren and Willenbrock, Scott},
abstractNote = {Extensions of the standard model with low-energy supersymmetry generically allow baryon- and lepton-number violating operators of dimension four and five, yielding rapid proton decay. The dimension-four operators are usually forbidden by matter parity. We investigate to what extent the appearance of dimension-five operators at the Planck scale may be constrained by the different grand-unified gauge groups. Dimension-five operators are suppressed in models based on E{sub 6} and SU(3){sub C}xSU(3){sub L}xSU(3){sub R}, where four matter fields do not form a gauge singlet. An intermediate scale offers the possibility to sufficiently suppress these dimension-five operators.},
doi = {10.1103/PHYSREVD.75.037702},
journal = {Physical Review. D, Particles Fields},
number = 3,
volume = 75,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}
  • Dimension-5 corrections to the gauge kinetic term of grand unified theories may capture effects of quantum gravity or string compactification. Such operators modify the usual gauge coupling unification prediction in a calculable manner. Here we examine SU(5), SO(10), and E(6) grand unified theories in the light of all such permitted operators and calculate the impact on the intermediate scales and the unification program. We show that in many cases at least one intermediate scale can be lowered to even 1-10 TeV, where a neutral Z{sup '} and possibly other states are expected.
  • The effect of radiative corrections in supersymmetric grand unified theories with soft- supersymmetry-breaking terms induced by N = 1 supergravity is analyzed. It is shown that any mass hierarchy present in the limit of unbroken supersymmetry is stable under radiative corrections induced by soft-supersymmetry-breaking terms, provided the theory does not contain a light singlet field that transforms as a singlet under the unbroken subgroup of the theory below the grand-unification scale.
  • We calculate the two loop contributions to the predictions of the mass scales in an SO(10) grand unified theory. We consider the modified unification scale boundary conditions due to the nonrenormalizable higher dimensional terms arising from quantum gravity or spontaneous compactification of extra dimensions in a Kaluza-Klein-type theory. We find the range of these couplings which allows left-right symmetry to survive till very low energy (as low as [similar to] TeV) and still be compatible with the latest values of sin[sup 2][theta][sub [ital W]] and [alpha][sub [ital s]] derived from CERN LEP. We consider both the situation when the left-rightmore » parity is broken and conserved. We consider both supersymmetric and nonsupersymmetric versions of the SO(10) theory. Taking the [ital D]-conserved non-SUSY case as an example we calculate the effects of moderate threshold uncertainties at the heavy scale, due to the unknown Higgs boson masses, on the gravity-induced couplings.« less
  • We have examined the electromagnetic weak decays of strange baryons induced by the dimension-five effective weak Hamiltonian of the form m/sub s/d-bar/sub L/sigma/sub munu/G/sup munu/s/sub R/ + m/sub s/s-bar/sub R/sigma/sub munu/G/sup munu/d/sub L/ and m/sub d/d-bar/sub R/sigma/sub munu/G/sup munu/s/sub L/ + m/sub d/s-bar/sub L/sigma/sub munu/G/sup munu/d/sub R/ originally due to Minkowski and others. In particular for ..sigma../sup +/..-->..p..gamma.., we find that the asymmetry ..cap alpha../sub ..sigma../approx. =-0.91 and the branching ratio B(..sigma../sup +/..-->..p..gamma..)approx. =0.42 x 10/sup -3/. The process ..cap omega../sup -/..--> lambda..K/sup -/ has also been discussed.
  • We discuss the smooth hybrid inflation scenario in the context of a simple supersymmetric SO(10) grand unified theory (GUT) in a 5D orbifold. In this GUT model, the SO(10) gauge symmetry is broken down to the Pati-Salam (PS) gauge group, SU(4){sub c} Multiplication-Sign SU(2){sub L} Multiplication-Sign SU(2){sub R}, by means of orbifold boundary conditions, and all matter and Higgs multiplets are placed only on the brane (PS brane) where only the PS symmetry is manifest. Further breaking of the Pati-Salam group to the standard model one is realized by means of vacuum expectation values of the Higgs multiplets (4,1,2) Circled-Plusmore » ( 4-bar ,1,2). The gauge coupling unification is successfully realized at M{sub GUT} = 4.6 Multiplication-Sign 10{sup 17} GeV after incorporating the threshold corrections of the Kaluza-Klein modes, with the compactification scale (assumed to be the same as the PS symmetry breaking scale) M{sub c} = v{sub PS} = 1.2 Multiplication-Sign 10{sup 16} GeV. We show that this orbifold GUT model can naturally lead us to smooth hybrid inflation, which turns out to be consistent with the Wilkinson Microwave Anisotropy Probe five-year data, with the M{sub GUT} and v{sub PS} predicted within the model.« less