Related papers: Phenomenological Estimation of Parameters in minim…
Some new physics beyond the Standard Model of particle physics, like Supersymmetry, Extra-dimensions etc., and their effect on the nature of different standard model phenomena are explored in this thesis. We discuss the power law scaling of…
We study analytically the general features of electroweak symmetry breaking in the context of the Minimal Supersymmetric Standard Model extended by one Higgs singlet. The exact analytical forms of the renormalization group evolutions of the…
I analyze the predictions for the strong gauge coupling, $\alpha_3(M_Z) $, and the top quark and light Higgs masses in the framework of gauge and bottom-tau Yukawa coupling unification in the minimal supersymmetric standard model. These…
Within the context of supergravity-coupled supersymmetry, fields which are gauge and global singlets are usually considered anathema. Their vacuum expectation values are shifted by quadratically divergent tadpole diagrams which are cutoff…
It is a well-known fact that the minimal renormalizable supersymmetric SU(5) model is ruled out assuming superpartner masses of the order of a few TeV. Giving up this constraint and assuming only SU(5) boundary conditions for the soft…
We present a comprehensive analysis of the Non-Minimal Supersymmetric Standard Model (NMSSM) for large values of $\tan\beta$, the ratio of the vacuum expectation values of the two Higgs doublets, which arise when we impose the constraint of…
Testing the stability of the electroweak vacuum in any extension of the Standard Model Higgs sector is of great importance to verify the consistency of the theory. Multi-scalar extensions as the Minimal Supersymmetric Standard Model…
We report on a preferred region of supersymmetric parameter space by t, b, tau Yukawa unification. We find a narrow region survives for mu > 0 (suggested by b --> s gamma and the anomalous magnetic moment of the muon) with A_0 \sim - 2…
Gauge mediation of supersymmetry breaking in the observable sector is an attractive idea, which naturally alleviates the flavour changing neutral current problem of supersymmetric theories. Quite generally, however, the number and quantum…
We examine the spectrum of supersymmetric particles predicted by grand unified theoretical (GUT) models where the electroweak symmetry breaking is accomplished radiatively. We evolve the soft supersymmetry breaking parameters according to…
The minimal supersymmetric standard model, and extensions, have stringent upper bounds on the mass of the lightest Higgs boson if perturbativity up to the Planck scale is assumed. We argue that these bounds are softened tremendously if the…
We present partial numerical results in the Minimal Supersymmetric Standard Model with soft breaking of supersymmetry, and radiative breaking of the electroweak symmetry. We impose the additional relation, bottom mass = tau mass at the GUT…
We show that the minimal renormalizable supersymmetric SO(10) GUT with the usual three generations of spinors has a Higgs sector consisting only of a "light" 10-dimensional and "heavy" 126, 126-bar and 210 supermultiplets. The theory has…
The restrictions on the lightest Higgs boson mass in the minimal supersymmetric models are briefly reviewed. The particle spectrum is considered in the framework of the simplest modification of NMSSM that allows to avoid the domain wall…
Assuming the existence of a functional relation among the Standard Model (SM) couplings gauge $\alpha_1$ and quartic $\lambda$, we determine the mass of the Higgs particle. Similar considerations for the top and bottom Yukawa couplings in…
Perturbative unification of soft supersymmetry--breaking (SSB) parameters is proposed in Gauge-Yukawa unified models. The method, which can be applied in any finite order in perturbation theory, consists in searching for renormalization…
New NLO b->sgamma calculations have become available using resummed radiative corrections. Using these calculations we perform a global fit of the supergravity inspired constrained minimal supersymmetric model (CMSSM). We find that the…
We study the evolution under the renormalization group of the restrictions on the parameters of the standard model coming from Non-Commutative Geometry, namely $m_{top} = 2\,m_W$ and $m_{Higgs} = 3.14 \, m_W$. We adopt the point of view…
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…
Properties and experimental predictions of a broad class of supergravity grand unified models possessing an $SU(5)$-type proton decay and $R$ parity are described. Models of this type can be described in terms of four parameters at the Gut…