相关论文: Neutron Majorana mass from exotic instantons

Neutrino oscillations have become well-known phenomenon; the measurements of neutrino mixing angles and mass squared differences are continuously improving. Future oscillation experiments will eventually determine the remaining unknown…

We discuss an alternative for Baryon-violating six quarks transitions, in the contest of low scale string theory. In particular, with $M_{S}=10\div 10^{3}\rm TeV$, such a transition can be mediated by two color-triplets,through a quartic…

We review and remark on models of radiatively induced neutrino Majorana masses and oscillations. It is pointed out that while the models are capable of accounting for the observed solar and atmospheric neutrino oscillation, some of them can…

We discuss non-perturbative corrections to the neutrino sector, in the context of a D-brane Pati-Salam-like model, that can be obtained as a simple alternative to $SO(10)$ GUT's in theories with open and unoriented strings. In such D-brane…

Recent theoretical developments have shown that extra spacetime dimensions can lower the fundamental GUT, Planck, and string scales. However, recent evidence for neutrino oscillations suggests the existence of light non-zero neutrino…

It is shown that neutrino oscillation and Majorana type neutrino are not compatible with Special Theory of Relativity. Instead of the Majorana type neutrino, traditional neutrino(no rest mass) is considered with additional assumptions that…

We show that when sterile Majorana neutrino masses are generated non-perturbatively through instantonic interactions in certain classes of string compactifications (e.g. Type IIA orientifold models with intersecting D-branes), then the…

We study how tiny Dirac neutrino masses consistent with experimental constraints can arise in string theory SM-like vacua. We use as a laboratory 4d ${\cal N}=1$ type IIA Calabi--Yau orientifold compactifications, and in particular recent…

Neutrino spin-flavour oscillations in the magnetic field, matter, and majoron fields are studied. The effective Lagrangian of Majorana neutrino interaction with a majoron field mediated by heavy neutrino is calculated. It is shown that the…

It is argued that the quantum gravity attractions dynamically generate tiny degenerate Majorana masses for the neutrinos. The unequal masses of the charged leptons then induce a computable neutrino mass matrix with splittings and mixings…

We discuss implications of open string theory in B-violating low energy physics. In particular, exotic instantons can dynamically generate effective six quarks' operator, leading to a neutron-antineutron transition. Proton is not…

Small Dirac masses for neutrinos are natural in models with singlet fermions in large extra dimensions with quantum gravity scale M_{\ast} \sim 1- 100 TeV. We study two modifications of the minimal model in order to obtain the mass scale…

Inspired by the experimental anomalies in neutrino physics and recent oscillation data from short baseline and another neutrino experiment, the realization of one extra neutrino flavor seem to be favoring. This extra flavor may change the…

The effective Majorana neutrino mass is evaluated by using the latest results of neutrino oscillation experiments. The problems of the neutrino mass spectrum,absolute mass scale of neutrinos and the effect of CP phases are addressed. A…

We determine the possible values of the effective Majorana neutrino mass $|< m > |= |\sum_j U_{ej}^2 m_j|$ in the different phenomenologically viable three and four-neutrino scenarios. The quantities $U_{\alpha j}$ ($\alpha =…

We explore the origin of Majorana masses within the majoron model and how this can lead to the generation of a distinguishable primordial stochastic background of gravitational waves. We first show how in the simplest majoron model only a…

We introduce a new effect in the neutrino oscillation phase which shows the neutrino-antineutrino oscillation is possible under gravity even if the rest masses of the corresponding eigenstates are same. This is due to CPT violation and…

Efficient oscillations between ordinary (active) and sterile neutrinos can occur only if Dirac and Majorana mass terms exist which are both small and comparable. It is shown that this can occur naturally in a class of string models, in…

A new economical model for neutrino masses is proposed in the context of brane bulk scenarios for particle physics, where global B-L symmetry of the standard model is broken spontaneously by a gauge singlet Higgs field in the bulk. This…

We study the modular symmetry anomaly in magnetized orbifold models. The non-perturbative effects such as D-brane instanton effects can break tree-level symmetry. We study which part of the modular symmetry is broken explicitly by Majorana…