Related papers: Non SUSY and SUSY one--step Unification
Recently it has been proposed that, in the framework of quantum field theory, both the Standard Model gauge and Yukawa interactions arise from a single gauge interaction in higher dimensions with supersymmetry. This leads to the unification…
Gauge coupling unification and the success of TeV-scale weakly interacting dark matter are usually taken as evidence of low energy supersymmetry (SUSY). However, if we assume that the tuning of the higgs can be explained in some unnatural…
We reexamine the renormalization group equations (RGEs) for the dimensionless and dimensionful parameters of the Minimal Supersymmetric Standard Model (MSSM), incorporating 1-loop thresholds. The inclusion of these thresholds necessarily…
We make a detailed analysis on the nucleon decay in the minimal supersymmetric $SU(5)$ 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…
I derive conservative upper bounds on the supersymmetry breaking parameter $m_{1/2}$ as a function of the strong coupling in the Standard Supersymmetric Model (SSM) using gauge coupling unification. I find that over more than $99\%$ of the…
Standard (level one) heterotic string models with standard model gauge group predict the unification of $SU(3)$ and $SU(2)$ gauge couplings whereas the $U(1)$ factor is unified modulo an unknown normalization factor $k_1$. On the other hand…
The derived modular invariant one-loop string effective coupling constant has been used to discuss the weak scale measurement constraints on minimal superstring models, minimal SUSY left-right string models and minimal left-right SUSY…
The issue of gauge unification in the (non-supersymmetric) Standard Model is reinvestigated. It is found that with just an additional fourth generation of quarks and leptons, $SU(3) \otimes SU(2) \otimes U(1)$ gauge couplings converge to a…
Supersymmetric gauge theories, in higher dimensions compactified in an orbifold, give a natural framework to unify the gauge bosons, Higgs fields and even the matter fields in a single multiplet of the unifying gauge symmetry. The extra…
We suggest simple ways of implementing Peccei-Quinn (PQ) symmetry to solve the strong CP problem in renormalizable SUSY $SO(10)$ models with a minimal Yukawa sector. Realistic fermion mass generation requires that a second pair of Higgs…
The string landscape suggests that the supersymmetry breaking scale can be high, and then the simplest low energy effective theory is the Standard Model (SM). We show that gauge coupling unification can be achieved at about 10^{16-17} GeV…
We perform a detailed study of the grand unified theories $SO(10)$ and $E(6)$ with left-right intermediate gauge symmetries of the form $SU(N)_L\otimes SU(N)_R \otimes \mathcal{G}$. Proton decay lifetime constrains the unification scale to…
The ununified standard model is an extension of the standard model that contains separate electroweak gauge groups for quarks and leptons. When it was originally proposed, data allowed the new gauge bosons to be quite light. We use recent…
We investigate the possibility to realize the unification of the Standard Model gauge interactions at the low scale in four dimensions. We find that the fields needed to define a minimal theory where baryon and lepton numbers are local…
We scan the complete parameter space of the supersymmetric standard model extended by a gauge singlet, which is compatible with the following constraints: universal soft supersymmetry breaking terms at the GUT scale, finite running Yukawa…
Convergence of the standard model gauge coupling constants to a common value at around $2\times 10^{16}$ GeV is studied in the context of orbifold theories where the modular symmetry groups for $T$ and $U$ moduli are broken to subgroups of…
The MSSM distinguishes itself from other GUT's by a successful prediction of many unrelated phenomena with a minimum number of parameters. Among them: a) Unification of the couplings constants; b)Unification of the masses; c) Proton decay;…
We show how gauge coupling unification near the Planck scale $M_P\sim 10^{19}$ GeV can be achieved in the framework of supersymmetry, facilitating a full unification of all forces with gravity. Below the conventional GUT scale $M_{GUT}\sim…
We calculate the weak scale MSSM spectrum starting from a heterotic string theory compactified on an anisotropic orbifold. Supersymmetry breaking is mediated by vector-like exotics that arise naturally in heterotic string theories. The…
A constraint on masses of superheavy gauge and Higgs multiplets at the grand unification (GUT) scale is obtained from the gauge coupling unification in the case of high-scale supersymmetry. We found that all of the particles may lie around…