Related papers: Updates and New Results in Models with Reduced Cou…
The Next to Minimal Supersymmetric Standard Model (NMSSM) with a Higgs-singlet coupling {\lambda} close to unity, moderate tan {\beta} and stop masses below 1 TeV minimizes the fine tuning of the electroweak scale, making possible that the…
We consider supersymmetric grand unified theory (GUT) with the gaugino mediated supersymmetry breaking and investigate a possibility to discriminate different GUT models in terms of predicted sparticle mass spectra. Taking two example GUT…
We review: 1) constraints on low energy supersymmetry from the search for Higgs boson and from precision data, 2) dependence of coupling unification on the superpartner spectrum, 3) naturalness and fine tuning in the minimal and non-minimal…
Motivated by the coupling unification problem, we propose a novel extension of the Minimal Supersymmetric Standard Model. One of the predictions of this extension is existence of new states neutral under SU(3)_c X SU(2)_w but charged under…
We consider N=1 supersymmetric gauge theories based on the group SU(N)_1 x SU(N)_2 x ... x SU(N)_k with matter content (N,N*,1,...,1) + (1,N,N*,...,1) + >... + (N*,1,1,...,N) as candidates for the unification symmetry of all particles. In…
Gauge-Higgs grand unification theories are models of gauge-Higgs unification that extend the electroweak group into a simple group that includes the color symmetry. The minimal option is a gauge-Higgs grand unification based on the SU(6)…
The commonly accepted notion of a weak unified coupling $\alpha_X \approx 0.04$, based on the assumption of the MSSM--spectrum, is questioned. It is suggested that the four--dimensional unified string coupling should very likely have an…
The simplest extension of the MSSM that does not contradict LEP II experimental bound on the lightest Higgs boson mass at $\tan\beta\sim 1$ is the modified Next-to-Minimal Supersymmetric Standard Model (MNSSM). We investigate the…
We review the theoretical and experimental status of minimal grand unified theories (GUTS), contrasting the failure of minimal non-supersymmetric $SU(5)$ with the success of the minimal supersymmetric $SU(5)$ and minimal supersymmetric…
Low-energy data, combined with renormalization group (RG) equations, can predict new physics at far higher energy scales. In this paper, we consider the possibility that the measured Higgs boson mass and top quark mass hint at a…
An introduction to the most important concepts in the subject of supersymmetric unified theories is presented. The emphasis is on the practical aspects leading to state-of-the-art calculations in this renascent subject. The topics covered…
This article reviews the Little Higgs models of electroweak symmetry breaking and their phenomenology. Little Higgs models incorporate a light composite Higgs boson and remain perturbative until a scale of order 10 TeV, as required by…
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…
The trinification model is an interesting extension of the Standard Model (SM) based on the gauge group $SU(3)_C\times SU(3)_L\times SU(3)_R$. We study its low-energy phenomenology by constructing a low-energy effective field theory,…
We investigate models of supersymmetric grand unification based on the gauge group SU(5). We consider models with non-universal gaugino masses and confront them with low energy constraints, including the Higgs boson mass and the Dark Matter…
We quantify and examine the uncertainties in predictions of the lightest $CP$ even Higgs boson pole mass $M_h$ in the Minimal Supersymmetric Standard Model (MSSM), utilising current spectrum generators and including some three-loop…
We explore the phenomenological predictions of a supersymmetric standard model, with a large extra dimension and unifying gauge couplings. The modified five dimensional renormalisation group equations make it possible to obtain light,…
The apparent unification of gauge couplings in Grand Unified Theories around 10$^{16}$ GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model. In this paper, an analysis of the measurements of the…
We re-examine the stop co-annihilation scenario of the Minimal Supersymmetric Standard Model, wherein a bino-like lightest supersymmetric particle has a thermal relic density set by co-annihilations with a scalar partner of the top quark in…
In the context of No-Scale F-SU(5), a model defined by the convergence of the F-lipped SU(5) Grand Unified Theory, two pairs of hypothetical TeV scale vector-like supersymmetric multiplets with origins in F-theory, and the dynamically…