Related papers: Neutrino models with a zero mass eigenvalue
In the seesaw model, the baryon asymmetry of the Universe can be generated by the decay of the lightest right-handed neutrino, nu_R. For a hierarchical spectrum of right-handed neutrinos, we show that there is a model independent upper…
We consider an extension of the Standard Model by right-handed neutrinos and we argue that, under plausible assumptions, a neutrino mass of ${\cal O}(0.1)\,{\rm eV}$ is naturally generated by the breaking of the lepton number at the Planck…
A four-neutrino spectrum with a sterile neutrino without significant involvement in the atmospheric and solar neutrino oscillation experiments has been recently advocated as the correct picture to explain all existing experimental data. We…
Recent data lead us to a simple and intriguing form of the neutrino mass matrix. In particular, we find solar neutrino oscillations to be nearly maximal (and rule out the small-angle MSW explanation of solar neutrino observations) if relic…
Neutrino masses provide one of the clearest indications of physics beyond the Standard Model. In this brief review, I discuss the main theoretical frameworks developed to account for them, with particular emphasis on scenarios in which…
After summarizing neutrino oscillation results I discuss high and low-scale seesaw mechanisms, with or without supersymmetry, as well as recent attempts to understand the pattern of neutrino mixing from flavor symmetries. I also mention the…
Neutrinos can play an important role in the evolution of the Universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos and we describe how the precision of…
Neutrinos provide a compelling avenue to explore physics beyond the Standard Model. This proceeding is a brief summary of a plenary talk given at the 12th Neutrino Oscillation Workshop (NOW2024). We present a discussion on various topics on…
I review the various mechanisms for obtaining nonzero neutrino masses. I focus on the possibility of adding one light singlet neutrino to the three known doublet neutrinos nu_e, nu_mu, and nu_tau to accommodate the totality of…
The origin of neutrino masses remains unknown. Both the vacuum mass and the dark mass generated by the neutrino interaction with dark matter (DM) particles or fields can fit the current oscillation data. The dark mass squared is…
In the first part of the talk, three key ideas proposed in the 1970s, and in particular their combined role in providing an understanding of the neutrino-masses as well as of the baryon-asymmetry of the universe, are expounded. The ideas in…
The discovery of neutrino masses suggests the likely existence of gauge singlet fermions that participate in the neutrino mass generation via the seesaw mechanism. The masses of the corresponding degrees of freedom can range from well below…
We present a comprehensive overview of an extension of the Standard Model that contains three right-handed (sterile) neutrinos with masses below the electroweak scale [the Neutrino Minimal Standard Model, (nuMSM)]. We consider the history…
The negative mass squared problem of the recent neutrino experiments from the five major institutions prompts us to speculate that, after all, neutrinos may be tachyons. There are number of reasons to believe that this could be the case.…
We have studied the scenario of baryogenesis via leptogenesis in an $A_4$ flavor symmetric framework considering type I seesaw as the origin of neutrino mass. Because of the presence of the fifth generation right handed neutrino the model…
Neutrino masses are yet unknown. We discuss the present state of effective electron anti-neutrino mass from $\beta$ decay experiments; effective Majorana neutrino mass from neutrinoless double-beta decay experiments; neutrino mass squared…
A new and radical scenario of the simple 2006 model of radiative neutrino mass is proposed, where there is no seesaw mechanism, i.e. neutrino masses are not inversely proportional to some large mass scale, contrary to the prevalent…
Seesaw mechanism has been a dominant paradigm in the discussion of neutrino masses. I discuss how this idea can be tested via a baryon number violating process such as $N-\bar{N}$ oscillation. Since the expected seesaw scale is high and the…
Neutrino oscillation and tritium beta decay experiments taken simultaneously into account are able to access the so far imperceptible absolute neutrino masses at the electronvolt level. The neutrino mass spectrum derived in this way is…
The sum of the masses of the three neutrino mass eigenstates is now constrained both from above and below, and lies between 55 and 6900 meV. The lower limit is set by neutrino oscillations and the fact that masses are non-negative. The…