相关论文: String Inspired Neutrino Mass Models
We review the issue of neutrino mass by concentrating on the minimal extensions of the standard model. In particular, we emphasize the role that gravitation may play in this regard and discuss the central aspects of the see-saw mechanism of…
The Standard Model (SM) with one right-handed neutrino per generation is revisited with presymmetry being the global $U(1)_{B-L}$ symmetry of an electroweak theory of leptons and quarks with initially postulated symmetric fractional…
We demonstrate how a class of non-supersymmetric $SO(10)$ GUT with asymmetric left-right theory $SU(2)_L \times U(1)_R \times U(1)_{B-L} \times SU(3)_C$ and Pati-Salam theory $SU(2)_L \times SU(2)_R \times SU(4)_C$ as intermediate symmetry…
We discuss symmetries and scenarios leading to quasi-degenerate neutrinos in type-I seesaw models. The existence of degeneracy in the present approach is not linked to any specific structure for the Dirac neutrino Yukawa coupling matrix…
The tiny neutrino masses are most naturally explained by seesaw mechanism through singlet right-handed neutrinos, which can further explain the matter-antimatter asymmetry in the Universe. In this Letter, we propose a new approach to study…
In the seesaw model with hierarchical Dirac masses, the neutrino mixing angle exhibits the behavior of a narrow resonance. In general, the angle is strongly suppressed, but it can be maximal for special parameter values. We delineate the…
We argue that with the discovery of neutrino mass effects at Super-Kamiokande there is a clear logical chain leading from the Standard Model through the MSSM and the recently developed Minimal Left Right Supersymmetric models with a…
The observed pattern of neutrino mass splittings and mixing angles indicates that their family structure is significantly different from that of the charged fermions. We investigate the implications of these data for the fermion mass…
Recent data from astrophysical and terrestrial experiments indicates large mixing angles in the neutral lepton sector and restricts the allowed regions of neutrino masses. In particular, the large mixing angles in the lepton sector are…
The light neutrino mass spectrum and mixing matrix of seesaw model including three right-handed neutrinos are studied for the most general case. An approximate formulae for mass eigenvalues, mixing matrix, and CP violation of neutrino…
I discuss two types of non-supersymmetric string model constructions that give at low energy exactly the Standard model (SM) with no additional matter/and or gauge group factors. The construction is based on D6 branes intersecting at angles…
A minimal extension of the Standard Model is proposed, where the observed left-handed neutrinos obtain naturally small Majorana masses from a one-loop radiative seesaw mechanism. This model has two candidates (one bosonic and one fermionic)…
We adapt the type II seesaw mechanism to the framework of the 3-3-1 model with right-handed neutrinos. We emphasize that the mechanism is capable of generating small masses for the left-handed and right-handed neutrinos and the structure of…
The Seesaw mechanism predicted tiny neutrino masses by postulating a new large scale in particle physics, using new theoretical ideas prompted by the Standard Model. It adds credence to a theoretical vista that is a quarter century old, and…
In a recent Letter we presented a systematic way of testing the seesaw origin of neutrino mass in the context of the Minimal Left-Right Symmetric Model. The essence of the program is to exploit lepton number violating decays of doubly…
Heavy right-handed neutrinos are highly motivated due to their connection with the origin of neutrino masses via the seesaw mechanism. If the right-handed neutrino Majorana mass is at or below the weak scale, direct experimental discovery…
The atmospheric and solar neutrino oscillation data suggest hierarchical neutrino masses with at least one large mixing. The simplest see-saw models for reconciling the two features are U(1) extensions of the SM with flavour dependent gauge…
We develop a see-saw model for neutrino masses and mixing with an S3\times Z3 symmetry. It involves an interplay of Type-I and Type-II see-saw contributions of which the former is subdominant. The S3 \times Z3 quantum numbers of the fermion…
We investigate the algebraic structure of the most general neutrino mass Hamiltonian and place the see-saw mechanism in an algebraic framework. We show that this Hamiltonian can be written in terms of the generators of an Sp(4) algebra. The…
We review the problem of neutrino masses and mixings in the context of Grand Unified Theories. After a brief summary of the present experimental status of neutrino physics, we describe how the see-saw mechanism can automatically account for…