Related papers: Neutrino Masses from Low Scale Partial Compositene…
Recently a minimalistic scenario has been developed to explain dark matter and tiny but nonzero neutrino masses. In this scenario, a new scalar called SLIM plays the role of the dark matter. Neutrinos achieve Majorana mass through a…
These lectures describe some aspects of the physics of massive neutrinos. After a brief introduction of neutrinos in the Standard Model, I discuss possible patterns for their masses. In particular, I show how the presence of a large…
We reconsider decays of pseudoscalar mesons (P) to neutrino pairs and possibly additional photons in presence of (light) Majorana neutrinos. For this purpose we derive a model-independent general parametrization of neutrino mass matrices…
Neutrino masses arise via a seesaw mechanism and its mass hierarchy, with assumption that heavy Majorana neutrino mass matrix subject to $\mu-\tau$ symmetry and invariant under a cyclic permutation, are evaluated. Within this scenario, the…
The theoretical basics of neutrino mass and mixing are reviewed. Dirac and Majorana masses are explained, and added together to produce the see-saw picture of the lightness of neutrinos. This picture predicts that neutrinos are Majorana…
The searches for an underlying pattern in neutrino masses have motivated different proposals for textures in the neutrino mass matrix, which is also related to particular arrangements of the mixing matrix. Current experimental…
The compelling experimental evidences for oscillations of solar and atmospheric neutrinos imply the existence of 3-neutrino mixing in vacuum. We briefly review the phenomenology of 3-neutrino mixing, and the current data on the 3-neutrino…
We consider various possibilities for generating neutrino masses in supersymmetric models with an additional U(1)' gauge symmetry. One class of models involves two extra U(1)' x U(1)'' gauge symmetries, with U(1)'' breaking at an…
Recent neutrino experiments have made very significant progresses and our knowledge of neutrino masses and mixing has considerably improved. In a model independent Monte Carlo approach, we have examined a very large class of textures, in…
We consider the low scale ($10$ - $100$ TeV) left-right symmetric model with "naturally" small neutrino masses generated through the inverse seesaw mechanism. The Dirac neutrino mass terms are taken to be similar to the masses of charged…
If neutrino masses have a radiative origin, their smallness can be naturally understood even when lepton number violation occurs near the weak scale. We analyze a specific model of this type wherein the neutrino masses arise as two--loop…
We study the perspective to observe lepton number violating signatures from heavy Majorana neutrino decays at colliders in view of the requirement to explain the light neutrino masses via the seesaw mechanism. In the minimal model with only…
A new idea for neutrino mass was proposed recently, where its smallness is not due to the seesaw mechanism, i.e. not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting…
We present general conditions on Dirac and Majorana mass terms under which a type-I seesaw mechanism can lead to three exactly massless neutrinos at the tree level. We depict several examples where the conditions are satisfied and relate…
The residual symmetry approach, along with a complex extension for some flavor invariance, is a powerful tool to uncover the flavor structure of the $3\times3$ neutrino Majorana mass matrix $M_\nu$ towards gaining insights into neutrino…
We discuss the connection between the origin of neutrino masses and their mixings which arises in a class of scenarios with radiatively induced neutrino masses. In these scenarios, the neutrino mass matrix acquires textures with two entries…
We determine the possible values of the effective Majorana neutrino mass $|< m > |= |\sum_j U_{ej}^2 m_j|$ in the different phenomenologically viable three and four-neutrino scenarios. The quantities $U_{\alpha j}$ ($\alpha =…
We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least…
The most plausible see-saw explanation of the smallness of the neutrino masses is based on the assumption that total lepton number is violated at a large scale and neutrinos with definite masses are Majorana particles. In this review we…
Recent atmospheric and solar neutrino experiments suggest that neutrinos have small but nonzero masses. They further suggest that mass eigenvalues have certain degree of hierarchical structures, and also some mixing angles are near-maximal…