Related papers: Do experiments suggest a hierarchy problem?
After summarizing the status of the Standard Model, we focus on the Hierarchy Problem and why we believe this strongly suggests the need for new physics at the TeV scale. We then concentrate on theories with extra dimensions and their…
Neutrino data lead via the see-saw mechanism to masses of the right handed neutrinos at the intermediate mass scale. Simple formalism is suggested which incorporates the quark - lepton symmetry and allows one to find properties of the…
Seesaw mechanism appears to be the simplest and most appealing way to understand small neutrino masses observed in recent experiments. It introduces three right handed neutrinos with heavy masses to the standard model, with at least one…
Matter effects modify the mixing and the effective masses of neutrinos in a way which depends on the neutrino mass hierarchy. Consequently, for normal and inverted hierarchies the oscillations and flavor conversion results are different.…
The recent evidence for neutrino oscillations stimulate us to discuss again the problem of fermion masses and mixings in gauge theories. In the standard model, several forms for quark mass matrices are equivalent. They become ansatze within…
A simple extension of the Standard Model providing TeV scale seesaw mechanism is presented. Beside the Standard Model particles and right-handed Majorana neutrinos, the model contains a singly charged scalar, an extra Higgs doublet and…
Recently a new mechanism has been proposed to cure the problem of fermion mass hierarchy in the Standard Model (SM) model. In this scenario, all SM charged fermions other than top quark arise from higher dimensional operators involving the…
The neutrino mass hierarchy, i.e., whether the $\nu_3$ neutrino mass eigenstate is heavier or lighter than the $\nu_1$ and $\nu_2$ mass eigenstates, is one of the remaining undetermined fundamental features of the neutrino Standard Model.…
The latest cosmological constraints on the sum of neutrino masses, in combination with the latest laboratory measurements on oscillations, provide ``decisive" Bayesian evidence for the normal neutrino mass hierarchy. We show that this…
One puzzle of neutrino masses and mixings is that they do not exhibit the kind of strong "hierarchy" that is found for the quarks and charged leptons. Neutrino mass ratios and mixing angles are not small. A possible reason for this is…
We discuss the possibility that the Higgs potential and electroweak scale are generated radiatively in a type-I seesaw scenario. A Higgs potential consistent with experimental constraints can be obtained in this hypothesis for a Majorana…
We find that minimizing the number of fine tuning relations in non-supersymmetric models can determine the scales at which some gauge symmetries beyond the standard model must break. We show that $SU(2)_R$ and $B-L$ gauge symmetries of the…
The Dirac masses of neutrinos can exhibit a strong hierarchy even if the Majorana masses of the right-handed neutrinos are degenerate and the hierarchy of the mass scales governing the oscillations of solar and atmospheric neutrinos is…
The insular nature of the Standard Model may be explained if the Higgs mass parameter is only sensitive to quantum corrections from physical states. Starting from a scale-free electroweak sector at tree-level, we postulate that quantum…
If neutrino masses are realized through the see-saw mechanism, can the right-handed neutrinos be produced and detected at present and future colliders? The answer is negative in the most popular see-saw scenarios for the simple reason that…
We argue that adding gauge-singlet real scalars to the Standard Model can both ameliorate the little hierarchy problem and provide a realistic source of Dark Matter. Masses of the scalars should be in the 1-3 TeV range, while the lowest…
A key question in cosmology is whether massive neutrinos exist on cosmic scales. Current cosmological observations have severely compressed the viable range for neutrino masses and even prefer phenomenologically an effective negative mass.…
The only experimentally observed phenomenon that lies outside the standard model of the electroweak interaction is neutrino oscillations. A way to try to unify the extensive neutrino oscillation data is to add a phenomenological mass term…
The existence of neutrino mass and mixing is a strong pointer towards physics beyond the standard model. An overview of the possibility of having neutrino masses in supersymmetric theories is attempted here. Some of the recent works…
Assuming hierarchical neutrino masses we calculate the heavy neutrino mass scale in the seesaw mechanism from experimental data on oscillations of solar and atmospheric neutrinos and quark-lepton symmetry. The resulting scale is around or…