Related papers: Does the hierarchy problem generate the seesaw sca…
As is well known, electroweak breaking in the MSSM requires substantial fine-tuning, mainly due to the smallness of the tree-level Higgs quartic coupling, lambda_tree. Hence the fine tuning is efficiently reduced in supersymmetric models…
Left right symmetric models (LRSM) are extensions of the standard model by an enlarged gauge group $SU(2)_L \times SU(2)_R \times U(1)_{B-L}$ where automatic inclusion of right handed fermions as $SU(2)_R$ doublets guarantees a natural…
We show that one of the ways of obtaining consistency between the idea of supersymmetric grand unification and an apparent low value of $\alpha_{strong}(M_Z)\simeq .11$ indicated by several low energy experiments is to have an intermediate…
Spontaneously broken Abelian gauge symmetries can explain the fermion mass hierarchies of the minimal supersymmetric standard model. In most cases it is assumed that the $U(1)_H$ symmetry is anomalous. However, non-anomalous models are also…
We examine many SO(10) models for their viability or otherwise in explaining all the fermion masses and mixing angles. This study is carried out for both supersymmetric and non-supersymmetric models and with minimal ($10+\bar{126}$) and…
Right handed neutrinos with mass of ${\cal O} \; (10^{12}-10^{13})$ GeV are required to implement the see-saw mechanism and generate neutrino masses capable of playing a role in structure formation. Moreover models of fermion masses often…
If the smallness of the mass of the sterile neutrino is to be explained by the see-saw mechanism, the off-diagonal entries of the mass matrix needs to be protected by some symmetry not far above the electroweak scale. We implement see-saw…
While the $S_3$ scalar leptoquark presents a possible tree-level explanation of the $b \to s \ell \ell$ flavour anomalies, it suffers from two conceptual problems which are often disregarded by model-builders. Firstly, the quantum numbers…
An ${\rm SU}(8)$ theory was previously found to be the minimal simple gauge group where all three-generational Standard Model (SM) fermions can be nontrivially embedded. It is maximally broken into a subgroup of ${\rm SU}(8)\to {\cal…
We consider the TeV scale left-right symmetric theory which can accommodate low scale seesaw mechanisms consistent with neutrino oscillation data and find new physics contributions to neutrinoless double beta decay. The model facilitates…
Symmetry-based ideas, such as the quark-lepton complementarity (QLC) principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to explain the observed mixing pattern of neutrinos. We argue that such symmetry relations need to…
Adding right-handed neutrino singlets and/or fermion triplets to the particle content of the Standard Model allows for the implementation of the seesaw mechanism to give mass to neutrinos and, simultaneously, for the construction of…
We study the left-right asymmetric model based on SU(3)_C \otimes SU(2)_L \otimes SU(3)_R \otimes U(1)_X gauge group, which improves the theoretical and phenomenological aspects of the known left-right symmetric model. This new gauge…
We studied a left-right symmetric model that can accommodate the neutrino dark energy (\nd) proposal. Type III seesaw mechanism is implemented to give masses to the neutrinos. After explaining the model, we study the consistency of the…
We propose a realistic theory based on the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes SU(3)_R \otimes U(1)_{X}}$ gauge group which requires the number of families to match the number of colors. In the simplest realization neutrino masses…
Within the framework of a Beyond Standard Model (BSM) with a local $SU(3)$ family symmetry, we report an updated fit of parameters which account for the known spectrum of quarks and charged lepton masses and the quark mixing in a $4\times…
We consider a U(1) gauge theory, minimally coupled to a massless Dirac field, where a higher-derivative term is added to the pure gauge sector, as in the Lee-Wick models. We find that this term can trigger chiral symmetry breaking at low…
We study a left--right symmetric model which contains only elementary gauge boson and fermion fields and no scalars. The phenomenologically required symmetry breaking emerges dynamically leading to a composite Higgs sector with a…
The gauge symmetry of the Standard Model is SU(3)_c x SU(2)_L x U(1)_Y for unknown reasons. One aspect that can be addressed is the low dimensionality of all its subgroups. Why not much larger groups like SU(7), or for that matter, SP(38)…
We calculate the region of the MSSM parameter space (i.e. $M_{1/2}$, $m_{0}$, $\mu$, \ldots) compatible with a correct electroweak breaking and a realistic top-quark mass. To do so we have included {\em all} the one-loop corrections to the…