相关论文: Pathways to Naturally Small Dirac Neutrino Masses

In this letter, we propose an extension of the scotogenic model where singlet Majorana particle can be dark matter (DM) without the need of a highly suppressed scalar coupling of the order $O(10^{-10})$. For that, the SM is extended with…

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 consider the class of models where Dirac neutrino masses at one loop and the dark matter stability can be obtained using only the global $U(1)_{B-L}$ symmetry already present in Standard Model. We discuss how the residual $\mathcal{Z}_n$…

In the context of a left-right extension of the standard model of quarks and leptons with the addition of a gauged $U(1)_D$ dark symmetry, it is shown how the electron may obtain a radiative mass in one loop and two Dirac neutrinos obtain…

A simple mechanism to generate Dirac masses for the neutrinos in SU(5) supersymmetric grand unified theory is proposed. The tiny Dirac masses are induced by the small mixing between the Higgs fields and another superheavy fields. The mixing…

We discuss the neutrino flavor structures in the Occam's razor approach for the Dirac neutrino mass matrices. We assume that the charged lepton mass matrix takes a diagonal base, while the right-handed Majorana neutrino mass matrix is also…

The symmetry between quarks and leptons suggests that neutrinos should have mass. As embodied in the grand unified theory SO(10) this yields masses that can only be detected by neutrino oscillations. Such oscillations could be very…

We analyze the structure of quark and lepton mass matrices under the hypothesis that they are determined from a minimum principle applied to a generic potential invariant under the $\left[U(3)\right]^5\otimes {\mathcal O}(3)$ flavor…

In SO(10) models with a vectorial fourth generation of down quarks and leptons, the structure of the neutrino Majorana and Dirac mass matrices generically coincide with those of up- and down-quarks, respectively. Then the small neutrino…

Recently it was proposed that the standard model (SM) degrees of freedom reside on a $(3+1)$-dimensional wall or ``3-brane'' embedded in a higher-dimensional spacetime. Furthermore, in this picture it is possible for the fundamental Planck…

The simplest possibility to generate small Majorana neutrino masses is the seesaw mechanism. However, the smallness of the observed neutrino masses can also be understood, if neutrino masses are generated by higher-dimensional operators…

In the framework of the baryogenesis via leptogenesis mechanism we study the link between the amount of baryon asymmetry and neutrino mass matrices. In particular, neglecting phases, we find that if the Dirac neutrino mass matrix is related…

Within the framework of a local SU(3) family symmetry model, we report a general analysis of the mechanism for neutrino mass generation and mixing, including light sterile neutrinos. In this scenario, ordinary heavy fermions, top and bottom…

The Majorana versus Dirac nature of neutrinos remains an open question. This is due, in part, to the fact that virtually all the experimentally accessible neutrinos are ultra-relativistic. Noting that Majorana neutrinos can behave quite…

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…

Besides the fact of parity violation in weak interactions, based on evidences from neutrino oscillation and tritium beta decay, a natural conjecture is that neutrinos may be spacelike particles with a tiny proper mass. A Dirac-type equation…

In this paper, we investigate lepton mass spectra, flavor mixing and CP violation with a modular $S^{}_4$ symmetry under the assumption that neutrinos are Dirac fermions. We find that the Majorana mass term can be forbidden by adjusting the…

We point out that the minimal seesaw model can provide a natural framework to accommodate tiny neutrino masses, while its experimental testability and notable predictiveness are still maintained. This possibility is based on the observation…

A beautiful understanding of the smallness of the neutrino masses may be obtained via the seesaw mechanism, whereby one takes advantage of the key qualitative distinction between the neutrinos and the other fermions: right-handed neutrinos…

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…