Related papers: Gauge Coupling Unification, SUSY Scale and Strong …
We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge theories on the T^2/Z_2 orbifold with general GUT breaking boundary conditions. For concreteness, we apply the obtained general formulae to the gauge coupling…
We discuss gauge coupling unification in models with additional 1 to 4 complete vector-like families, and derive simple rules for masses of vector-like fermions required for exact gauge coupling unification. These mass rules and the…
I review the unification of gauge couplings of strong, weak and electro-magnetic interactions. I start by recalling the history of the most important prediction of low-energy supersymmetry: the correct value of the weak mixing angle tied to…
We calculate the gauge couplings in the dual standard model. These values are consistent with an associated GeV mass scale, and predict the weak mixing angle to be ${\sin^2 \theta_w} (M_Z) \sim 0.22$.
We consider the possibility of gauge coupling unification within the simplest realizations of the $\mathrm{SU(3)_c \times SU(3)_L \times SU(3)_R \times U(1)_{X}}$ gauge theory. We present a first exploration of the renormalization group…
We consider states in the adjoint representation of the Standard Model gauge group as messengers for mediation of supersymmetry (SUSY) breaking. These new messengers can shift the gauge coupling unification to the string scale at…
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 purpose of this paper is threefold: a) Check if the rather poor Standard Model (SM) fit to all electroweak data can be improved in its minimal supersymmetric extension (MSSM); b) Check what constraints present electroweak data has on…
We present an updated assessment of the viability of t-b-tau Yukawa coupling unification in supersymmetric models. For the superpotential Higgs mass parameter mu>0, we find unification to less than 1% is possible, but only for GUT scale…
In the present paper we demonstrate the possibility of the [SUSY(5)]^3 SUSY unification at the energy scale $\mu_{GUT}\approx 10^{18.3} GeV$ with the value of GUT inverse finestructure constant $\alpha_{GUT}^{-1}\approx 34.4$, which is very…
We study the finely tuned SSM, recently proposed by Arkani-Hamed and Dimopoulos, at the one loop level. The runnings of the four gaugino Yukawa couplings, the mu term, the gaugino masses, and the Higgs quartic coupling are computed. The…
Extrapolating the coupling strengths to very high energies, one finds that they do not converge to a single coupling constant, as expected in the simplest gauge theory of Grand Unification, the SU(5) theory. We find that the coupling…
We show that contrary to first expectations realistic three generation supersymmetric intersecting brane world models give rise to phenomenologically interesting predictions about gauge coupling unification. Assuming the most economical way…
The string theory predicts the unification of the gauge couplings and gravity. The minimal supersymmetric Standard Model, however, gives the unification scale $\sim 2\times 10^{16}$ GeV which is significantly smaller than the string scale…
In theories with TeV string scale and sub-millimeter extra dimensions the attractive picture of logarithmic gauge coupling unification at $10^{16}$ GeV is seemingly destroyed. In this paper we argue to the contrary that logarithmic…
We start a systematic investigation of the possibility to have supersymmetry (SUSY) to be an asymptotic state of the gauge theory in the high energy (UV) limit, due to the renormalization group running of coupling constants of the theory.…
We calculate the values and 1 sigma ranges of the running quark and lepton Yukawa couplings as well as of the quark mixing parameters at various energy scales, i.e. at M_Z, 1 TeV, 3 TeV, 10 TeV and at the GUT scale, to provide useful input…
We recalculate the two-loop beta functions for three gauge couplings taking into account all low energy threshold corrections in split supersymmetry (split-SUSY) which assumes a very high scalar mass scale M_S. We find that, in split-SUSY…
Supersymmetric extensions of the Standard Model generally give a theoretical upper limit on the lightest Higgs boson mass which may be uncomfortably close to the current experimental lower bound of $m_h$ > 114 GeV. Here we show ways in…
Grand Unified Theories (GUTs) are attractive candidates for more fundamental elementary particle theories. They can not only unify the Standard Model (SM) interactions but also different types of SM fermions, in particular quarks and…