Towards a viable grand unified model with M G ∼ M string and M I ∼ 10 12 GeV

Towards a viable grand unified model with M G ∼ M string and M I ∼ 10 12

Nucleon Decay in the Minimal Supersymmetric SU (5) Grand Unification

We make a detailed analysis on the nucleon decay in the minimal super-symmetric SU(5) grand unified model. We find that a requirement of the unification of three gauge coupling constants leads to a constraint on a mass M H C of color-triplet Higgs multiplet as 2×10 13 GeV ≤ M H C ≤ 2×10 17 GeV, taking both weak-and GUT-scale threshold effects into account. Contrary to the results in the previou...

Vanishing Corrections on Intermediate Scale and Implications for Unification of Forces

In two–step breaking of a class of grand unified theories including SO(10), we prove a theorem showing that the scale (MI) where the Pati–Salam gauge symmetry with parity breaks down to the standard gauge group, has vanishing corrections due to all sources emerging from higher scales (μ > MI) such as the one–loop and all higher–loop effects, the GUT–threshold, gravitational smearing, and string...

String Unification and Threshold Corrections

The interpretation of the apparent unification of gauge couplings within supersymmetric theories depends on uncertainties induced through heavy particle thresholds. While in standard grand unified theories these effects can be estimated easily, the corresponding calculations are quite complicated in string unified theories and do exist only in models with unbroken E6. We present results for hea...

Perturbative SO(10) Grand Unification

We consider a phenomenologically viable SO(10) grand unification model of the unification scale MG around 10 16 GeV which reproduces the MSSM at low energy and allows perturbative calculations up to the Planck scale MP or the string scale Mst. Both requirements strongly restrict a choice of Higgs representations in a model. We propose a simple SO(10) model with a set of Higgs representations {2...