The Missing Doublet Model Revamped

Abstract

We revisit the Missing Doublet Model (MDM) as a means to address the apparent difficulties of the minimal $SU(5)$ supergravity model in dealing with the doublet-triplet splitting problem, the prediction of ${\alpha }_3(M_Z)$, and the proton lifetime. We revamp the original MDM by extending its observable sector to include fields and interactions that naturally suppress the dimension-five proton decay operators and that allow see-saw neutrino masses. We also endow the model with a hidden sector which (via gaugino condensation) triggers supersymmetry breaking of the desired magnitude, and (via hidden matter condensation) yields a new dynamical intermediate scale for the right-handed neutrino masses ($\sim10^{10}\GeV$), and provides an effective Higgs mixing parameter $\mu$. The model is consistent with gauge coupling unification for experimentally acceptable values of ${\alpha }_3(M_Z)$, and with proton decay limits even for large values of $\tan \beta$. The right-handed neutrinos can be produced subsequent to inflation, and their out-of-equilibrium decays induce a lepton asymmetry which is later reprocessed (via sphaleron interactions) into a baryon asymmetry at the electroweak scale. The resulting see-saw neutrino masses provide a candidate for the hot dark matter component of the Universe ($m_{ν_τ}\sim{\cal O}(10\eV)$) and are consistent with the MSW solution to the solar neutrino problem. We finally compare the features of this traditional GUT model with that of the readily string-derivable $SU(5)\times U(1)$ model, and discuss the prospects of deriving the revamped MDM from string theory.

22 pages, 1 figure (uuencoded)

References in corpus (20)

• Supersymmetry Breaking in the Early Universe
• Precision Corrections to Supersymmetric Unification
• String Consistency for Unified Model Building
• The strong coupling, unification, and recent data
• String GUTs
• Could the Supersymmetric Higgs Particles Naturally be Pseudo-Goldstone Bosons?
• ${\sin }^2{\theta }_W(M_Z)$ ~in the MSSM and Unification of Couplings
• Exotic Non-Supersymmetric Gauge Dynamics from Supersymmetric QCD
• A Complete Supersymmetric SO(10) Model
• SUSY SU(6) GIFT for doublet-triplet splitting and fermion masses
• Constraints on the Minimal SUSY SO(10) Model from Cosmology and the $b\to s\gamma$ Decay
• Exact Results in Softly Broken Supersymmetric Models
• Effects of Gravitational Smearing on Predictions of Supergravity Grand Unification
• "An SO(10) Solution to the Puzzle of Quark and Lepton Masses"
• Limit on the Color-Triplet Higgs Mass in the Minimum Supersymmetric SU(5) Model
• Low ${\alpha }_{strong}(M_Z)$, Intermediate Scale SUSY SO(10) GUT and Its Implications
• Supersymmetries in Free Fermionic Strings
• Intermediate Scales in SUSY SO(10), b-τunification and Hot Dark Matter Neutrinos
• Planck Scale Physics and the Testability of SU(5) Supergravity GUT
• Effective couplings and Perturbative Unification

Cited by in corpus (8)

• Geometric theory on the elasticity of bio-membranes
• Anomalous U(1) symmetry and missing doublet SU(5) model
• On Supersymmetric b-tau Unification, Gauge Unification, and Fixed Points
• Supersymmetry: From the Fermi Scale to the Planck Scale
• Phenomenology with Supersymmetric Flipped SU(6)
• b-tau Unification and neutrino masses in SU(5) extensions of the MSSM with radiative electroweak symmetry breaking
• Realistic Supersymmetric SU(6)
• Soft SUSY breaking contributions to proton decay