Related papers: Perturbative $\lambda$-Supersymmetry and Small $\k…
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…
The two-loop Higgs mass upper bounds are reanalyzed. Previous results for a cutoff scale $\Lambda\approx$ few TeV are found to be too stringent. For $\Lambda=10^{19}$ GeV we find $M_H < 180 \pm 4\pm 5$ GeV, the first error indicating the…
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 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…
We point out that the $\mu$-problem in theories in which supersymmetry breaking is communicated to the observable sector by gauge interactions is more severe than the one encountered in the conventional gravity-mediated scenarios. The…
We present an economical theory of natural electroweak symmetry breaking, generalizing an approach based on deconstruction. This theory is the smallest extension of the Standard Model to date that stabilizes the electroweak scale with a…
Motivated by the absence, so far, of any direct signal of conventional low-energy supersymmetry, we explore the consequences of making the lightest Higgs boson in supersymmetry relatively heavy, up to about 300 GeV, in the most…
We analyse the stability lower bounds on the Standard Model Higgs mass by carefully controlling the scale independence of the effective potential. We include resummed leading and next-to-leading-log corrections, and physical pole masses for…
It is challenging to explain the tentative 125 GeV Higgs signal in the Minimal Supersymmetric Standard Model (MSSM) without introducing excessive fine-tuning, and this motivates the study of non-minimal implementations of low energy…
The lack of evidence for new physics beyond the standard model at the LHC points to a paucity of new particles near the weak scale. This suggests that the weak scale is tuned and that supersymmetry, if present at all, is realized at higher…
Composite Higgs models can trivially satisfy precision-electroweak and flavour constraints by simply having a large spontaneous symmetry breaking scale, f > 10 TeV. This produces a 'split' spectrum, where the strong sector resonances have…
We argue for a relation between the supersymmetry breaking scale and the measured value of the dark energy density $\Lambda$. We derive it by combining two quantum gravity consistency swampland constraints, which tie the dark energy density…
The evaluation of high-energy cross sections involving the SM Higgs boson requires the use of the Higgs running coupling $\lambda(\mu)$. Taking $\mu$ to be equal to the center-of-mass energy $\sqrt{s}$ of the scattering process, the…
If there exists an arbitrary supersymmetric U(1) gauge factor at the TeV scale, under which the two Higgs superfields H_{1,2} of the standard model are nontrivial, and if there is also a singlet superfield S such that the H_1 H_2 S term is…
Measuring the Higgs couplings accurately at colliders is one of the best routes for finding physics Beyond the Standard Model (BSM). If the measured couplings deviate from the SM predictions, then this would give rise to energy-growing…
The appearance of a broken supersymmetric U(1) gauge factor at the TeV scale is relevant for several reasons. If it truly exists, then one important consequence is that at the 100 GeV energy scale, the two-doublet Higgs structure is of a…
In the Higgs sector of the Minimal Supersymmetric Standard Model, the mass of the pseudoscalar $A$ is an independent parameter together with $\tan \beta \equiv v_2/v_1$. If $m_A$ is small, then the process $e^+ e^- \to h + A$ is…
We reconsider the possibility that all standard model gauge couplings blow up at a common scale in the ultraviolet. The simplest implementation of this idea assumes supersymmetry and the addition of a single vector-like generation of matter…
We propose a minimal supersymmetric Twin Higgs model that can accommodate tuning of the electroweak scale for heavy stops better than 10% with high mediation scales of supersymmetry breaking. A crucial ingredient of this model is a new…
We revisit four generations within the context of supersymmetry. We compute the perturbativity limits for the fourth generation Yukawa couplings and show that if the masses of the fourth generation lie within reasonable limits of their…