Related papers: Vacuum Stability Conditions for New $SU(2)$ Multip…
We analyze one-loop vacuum stability, perturbativity, and phenomenological constraints on a complex singlet extension of the Standard Model (SM) scalar sector containing a scalar dark matter candidate. We study vacuum stability…
In this work we review the status of tree-level vacuum stability in general two-Higgs doublet models. We also discuss the problem of Normal minima in some classes of potentials. In some of these potentials, Normal minima can coexist leading…
We derive analytic necessary and sufficient conditions for the vacuum stability of the left-right symmetric model by using the concepts of copositivity and gauge orbit spaces. We also derive the conditions sufficient for successful symmetry…
We introduce a novel set of stability conditions for vacua with broken Lorentz symmetry. The first class of conditions require that the energy be minimized under small geometric deformations, which translates into requiring the positivity…
We investigate the parameter space of the Standard Model enhanced by a gauge singlet real scalar $S$. Taking into account all the theoretical and experimental constraints, we show the allowed parameter space for two different types of such…
We propose a two component dark matter set-up by extending the Standard Model with a singlet and a hypercharge-less triplet scalars, each of them being odd under different $Z_2$ symmetries. We observe that the inter-conversion between the…
We study several aspects of electroweak vacuum metastability when an extra gauge singlet scalar, a viable candidate for a dark matter particle, is added to the standard model of particle physics, which is assumed to be valid up to the…
In this work, we delve to investigate a feasible range of dark matter (DM) masses within a non-supersymmetric $SO(10)$ Grand Unified Theory (GUT) scalar dark matter model, in freeze-out scenario. This model includes a singlet scalar denoted…
We summarize our analysis for the vacuum stability of the superweak extension of the standard model. The parameter space allowed by the $W$-boson mass measurements and collider searches for a new scalar particle are also presented. The…
We study the allowed parameter space of the scalar sector in the superweak extension of the standard model (SM). The allowed region is defined by the conditions of (i) stability of the vacuum and (ii) perturbativity up to the Planck scale,…
The most general $SU(2)\times U(1)_Y$-symmetric quartic potential with two Higgs doublets, subject to an only softly broken discrete symmetry $(\phi_1,\phi_2)\to(-\phi_1,\phi_2)$, is considered. At tree-level, analytic bounds on the…
Consistency of the unconventional view of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom requires that Coleman-De Luccia tunneling rates to vacua with negative cosmological constant should be…
The inert scalar doublet model of dark matter can be valid up to the Planck scale. We briefly review the bounds on the model in such a scenario and identify parameter spaces that lead to absolute stability and metastability of the…
In this thesis, various extensions of the scalar sector have been considered comprising of different ${SU(2)_L}$ multiplets. If the extended scalar sector participates in the electroweak symmetry breaking then these extra scalars need to…
By applying copositivity criterion to the scalar potential of the economical $3-3-1$ model, we derive necessary and sufficient bounded-from-below conditions at tree level. Although these are a large number of intricate inequalities for the…
We consider the most general SU(3) singlet space of gauged N=8 supergravity in four-dimensions. The SU(3)-invariant six scalar fields in the theory can be viewed in terms of six real four-forms. By exponentiating these four-forms, we…
The stability of the electroweak vacuum imposes important constraints on new physics models. Such new physics models may introduce one or more new thermal phases with a lower free energy than that of the electroweak vacuum. In this case,…
We study the existence and stability of classical de Sitter solutions of type II supergravities with parallel Dp-branes and orientifold Op-planes. Together with the dilaton and volume scalar fields, we consider a third one that…
We consider a $SU(3)_c \times SU(3)_L \times U(1)_X$ model from a $SU(6)$ Grand Unified Theory (GUT). In order to explain the anomalous magnetic moments of muon and electron, we introduce two new scalar triplets without vacuum expectation…
A consistent theoretical description of physics at high energies requires an assessment of vacuum stability in either the Standard Model or any extension of it. Especially supersymmetric extensions allow for several vacua and the choice of…