相关论文: Two-loop-induced neutrino masses: A model-independ…
We perform a systematic study of the $d=5$ Weinberg operator at the one-loop level. We identify three different categories of neutrino mass generation: (1) finite irreducible diagrams; (2) finite extensions of the usual seesaw mechanisms at…
We provide a complete systematic classification of all two-loop realizations of the dimension four operator for Dirac neutrino masses. Our classification is multi-layered, starting first with a classification in terms of all possible…
We propose a two-loop induced neutrino mass model, in which we show some bench mark points to satisfy the observed neutrino oscillation, the constraints of lepton flavor violations, and the relic density in the co-annihilation system…
A plausible explanation for the lightness of neutrino masses is that neutrinos are massless at tree level, with their mass (typically Majorana) being generated radiatively at one or more loops. The new couplings, together with the…
Various mechanisms have been developed to explain the origin of Majorana neutrino masses. One of them is radiative mass generation. Two-loop mass generation is of particular interest because the masses and couplings of new particles…
We study Majorana neutrino masses induced by D-brane instanton effects in magnetized orbifold models. We classify possible cases, where neutrino masses can be induced. Three and four generations are favored in order to generate neutrino…
General classes of mechanisms for generating small neutrino masses are surveyed from a top-down (superstring) perspective. In particular, string constructions have motivated various possibilities involving higher-dimensional operators,…
One-loop radiative Majorana neutrino masses through the exchange of scalars have been considered for many years. We show for the first time how such a one-loop mass is also possible through the exchange of vector gauge bosons. It is based…
The addition of $m$ singlet right-handed neutrinos to the Standard Model leads to radiatively generated mass corrections for the $SU(2)_L $ doublet neutrinos. For those neutrinos which are massless at the tree level after this addition,…
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…
We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of…
Effective operators relevant for generating small Majorana masses for the neutrinos in the Standard Model will be considered. These operators serve as a useful guide for building models of neutrino mass. Some of these operators are…
We present a classification of SU(3) x SU(2) x U(1) gauge invariant \Delta L = 2 (L being lepton number) effective operators relevant for generating small Majorana neutrino masses. Operators of dimension up to 11 have been included in our…
We discuss the simplest models for the generation of neutrinos masses at tree level and one-loop level. The realization of the different seesaw mechanisms in the context of renormalizable SU(5) and SO(10) theories is reviewed. A new…
We have investigated in detail a model that contains an additional SU(2) singlet and triplet scalar fields than the Standard Model (SM). This allows the radiative generation of Majorana neutrino masses at two-loop order with the help of…
We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge.…
We show renormalization group invariants in neutrino sector. These are found from a simple analytical discussion of Majorana mass matrix for light neutrinos. It is shown that the invariants are obtained by taking ratios among elements of…
We propose a model with radiatively induced neutrino mass at two-loop level, applying modular $A_4$ symmetry. The neutrino mass matrix is formulated where the structure of associated couplings are restricted by the symmetry. Then we show…
In this paper we consider possible mechanisms to generate small Majorana neutrino masses for active neutrinos in the scenario of gauge-Higgs unification, a candidate for physics beyond the standard model. We stress that it is non-trivial to…
This is a review for Reports of Progress in Physics. After an introduction we start by explaining the different neutrino masses corresponding to different types of neutrinos, Dirac or Majorana, in section 2. In section 3 we discuss the main…