Related papers: Neutrino Mass
An alternative to the famous see-saw mechanism is proposed to explain the smallness of the neutrino masses (if present). This model involves a fourth family which mixes very little with the other three. It contains one heavy neutrino (mN >…
Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate the heavy neutrino masses under the hypotheses that the mixing in the Dirac leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that $M_{\nu}…
If neutrino masses are obtained via the canonical seesaw mechanism, based on an underlying 2X2 mass matrix, unitarity violation of the neutrino mixing matrix is unavoidable, but its effect is extremely small. On the other hand, in the…
We discuss some known approaches and results as well as few new ideas concerning origins and nature of neutrino mass. The key issues include (i) connections of neutrino and charged fermions masses, relation between masses and mixing, energy…
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…
A brief overview of the phenomenology related to the seesaw mechanism and the baryogenesis via leptogenesis is presented.
We derive the lower bound on absolute scale of lightest neutrino mass for normal hierarchy and inverted hierarchy pattern of light neutrinos by studying the new physics contributions to charged lepton flavour violating decays and…
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…
We present a simple observation for neutrino mixings and masses which arises naturally in dimensional deconstruction models. There are two essential ingredients of such models: (i) the presence of a symmetry mediated by the link fields…
The various experiments on neutrino oscillation evidenced that neutrinos have indeed non-zero masses but cannot tell us the absolute neutrino mass scale. This scale of neutrino masses is very important for understanding the evolution and…
The discovery of neutrino mass establishes the need for physics beyond the Standard Model. I summarize the status of two- and three-neutrino oscillation parameters from current solar, atmospheric, reactor and accelerator data. Future…
String theories in principle address the origin and values of the quark and lepton masses. Perhaps the small values of neutrino masses could be explained generically in string theory even if it is more difficult to calculate individual…
We discuss a radiative type-I seesaw. In these models, the radiative generation of Dirac neutrino masses allows to explain the smallness of the observed neutrino mass scale for rather light right-handed neutrino masses in a type-I seesaw.…
The triplet or type-II seesaw mechanism is the simplest way to endow neutrinos with mass in the Standard Model (SM). Here we review its associated theory and phenomenology, including restrictions from $S$, $T$, $U$ parameters, neutrino…
Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate…
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 study parameters of an extended standard model. The neutrino sector is enlarged by one or two right-handed singlet fields and the Higgs sector contains one additional doublet. One-loop radiative corrections generate the mass for the…
The recently proposed "mini-seesaw mechanism" combines naturally suppressed Dirac and Majorana masses to achieve light Standard Model neutrinos via a low-scale seesaw. A key feature of this approach is the presence of multiple light (order…
A brief review of the problem of neutrino masses and oscillations is given. In the beginning we present an early history of neutrino masses, mixing and oscillations. Then we discuss all possibilities of neutrino masses and mixing (neutrino…
The observed pattern of lepton mixing does not give an evidence of the seesaw. It is easier to disprove seesaw showing that one of the alternatives gives dominant contribution to the neutrino mass. We consider alternative mechanisms based…