Related papers: Is our vacuum global in a 331 model with three tri…
We analyze the vacuum structure of the Babu--Nandi--Tavartkiladze (BNT) model of neutrino mass generation, in which the Standard Model is extended by an $SU(2)_L$ scalar quadruplet with hypercharge $Y=3/2$ and a vector-like $SU(2)_L$…
We investigate a particle physics model for cosmic inflation based on the following assumptions: (i) there are at least two complex scalar fields; (ii) the scalar potential is bounded from below and remains perturbative up to the Planck…
We consider the addition to the Standard Model of a scalar $SU(2)$ multiplet $\Delta_n$ with dimension $n$ going from $1$ to $6$. The multiplet $\Delta_n$ is assumed to have null vacuum expectation value and an arbitrary (free) hypercharge.…
We consider the quark sector of theories containing three scalar SU(2)_L doublets in the triplet representation of A4 (or of S4) and three generations of quarks in arbitrary A4 (or S4) representations. We show that, for all possible choices…
We consider an extension of the Standard Model with one or more scalar multiplets beyond the Higgs doublet $\Phi$. The additional scalar multiplets are supposed to carry arbitrary hypercharges. We prove that, in such a model, if the field…
An electroweak model with running coupling constants described by an energy dependent entire function is utraviolet complete and avoids unitarity violations for energies above 1 TeV. The action contains no physical scalar fields and no…
A measurement of the Higgs trilinear self coupling $\lambda_{hhh}$ will test the Standard Model Higgs potential. But can it reveal information that cannot be learned otherwise? By analyzing several simple extensions of the Standard Model…
The Georgi-Machacek model, introducing a complex and a real scalar triplet as additional components of the electroweak symmetry breaking sector, enables substantial triplet contributions to the weak gauge boson masses, subject to the…
We explore dynamics of cosmological models with a nonminimally coupled scalar field evolving on a spatially flat Friedmann-Lemaitre-Robertson-Walker background. We consider cosmological models including the Hilbert-Einstein curvature term…
In the original version of the minimal SU(3)_C x SU(3)_L x U(1)_N model the masses of all quarks are correctly obtained by introducing three scalar triplets into the model, meanwhile the lepton mass generation requires the introduction of…
Classically scale-invariant models are attractive not only because they may offer a solution to the long-standing gauge hierarchy problem, but also due to their role in facilitating strongly supercooled cosmic phase transitions. In this…
A realistic SU(3)_C x SU(3)_W unified theory is constructed with a TeV sized extra dimension compactified on the orbifold S_1/Z_2, leaving only the standard model gauge group SU(3)_C x SU(2)_L x U(1)_Y unbroken in the low energy 4D theory.…
In sufficiently complex models with many parameters that are unknown or undetermined from first principles, a small coupling or mass can naturally arise even if it is not protected by a symmetry or a result of some dynamics. For the…
By following previous work on this subject, we investigate the issue of the instability of the electroweak vacuum against the top loop corrections by performing an accurate analysis of a Higgs-Yukawa model. We find that, when the physical…
The effective potential has been previously calculated through three-loop order, in Landau gauge, for a general renormalizable theory using dimensional regularization. However, dimensional regularization is not appropriate for softly broken…
We consider the electroweak theory with an additional Higgs triplet at one loop using the hybrid renormalization scheme based on $\alpha_{\rm EM}$, $G_F$ and $M_Z$ as input observables. We show that in this scheme loop corrections can be…
We describe the non-minimal Standard Model, consisting of minimalistic extensions of the Standard Model, which for all we know is the theory of the universe, able to describe all of the universe from the beginning of time. Extensions…
We investigate the standard model (SM) with the extension of a charged scalar having fractional electromagnetic charge of $-1/3$ unit and with lepton and baryon number violating couplings at tree level. Without directly taking part in the…
Some versions of the electroweak SU(3)$_L\otimesU(1)_X$ models cannot be treated within perturbation theory at energies of few TeV. An extended version for these models is proposed which is perturbative even at TeV scale posing no…
One of the simplest extensions of the Standard Model is the inclusion of an additional scalar multiplet, and we consider scalars in the $SU(2)_L$ singlet, triplet, and quartet representations. We examine models with heavy neutral scalars,…