Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTesting the minimal $S_4$ model of neutrinos with the Dirac and Majorana phases
133
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We propose two new simple lepton flavor models in the framework of the $S_4$ flavor symmetry. The neutrino mass matrices, which are given by two complex parameters, lead to the inverted mass hierarchy. The charged lepton mass matrix has the 1-2 lepton flavor mixing, which gives the non-vanishing reactor angle $theta_{13}$. These models predict the Dirac phase and the Majorana phases, which are testable in the future experiments. The predicted magnitudes of the effective neutrino mass for the neutrino-less double beta decay are in the regions as $32~text{meV}lesssim |m_{ee}|lesssim 49~text{meV}$ and $34~text{meV}lesssim |m_{ee}|lesssim 59~text{meV}$, respectively. These values are close to the expected reaches of the coming experiments. The total sum of the neutrino masses are predicted in both models as $0.0952~text{eV}lesssim sum m_ilesssim 0.101~text{eV}$ and $0.150~text{eV}lesssim sum m_ilesssim 0.160~text{eV}$, respectively.
rate research
Read More
Massive neutrinos can have helicity $s_{parallel} eq -1$. Neutrino helicity changes when the neutrino interacts with an external magnetic field and it is possible that the left-handed neutrinos born inside the Sun or a supernova could leave their sources with a different helicity. Since Dirac and Majorana neutrinos have different cross sections in the scattering on electrons for different neutrino helicities, a change in the final neutrino helicity may generate a different number of events and spectra in terrestrial detectors when astrophysical neutrinos have travelled regions with strong magnetic fields. In this work, we show that looking for these effects in solar neutrinos, it could be possible to set bounds in the neutrino properties such as the neutrino magnetic moment. Furthermore, for neutrinos coming from a supernova, we show that even in the case of an extremely small neutrino magnetic moment, $mu_ u sim 10^{-19}mu_B$, there will be measurable differences in both the number of events and in the spectra of Majorana and Dirac neutrinos.
Gluinos and neutralinos, supersymmetric partners of gluons and neutral electroweak gauge and Higgs bosons, are Majorana particles in the Minimal Supersymmetric Standard Model [MSSM]. Decays of such self-conjugate particles generate charge symmetric ensembles of final states. Moreover, production channels of supersymmetric particles at colliders are characteristically affected by the Majorana nature of particles exchanged in the production processes. The sensitivity to the Majorana character of the particles can be quantified by comparing the predictions with Dirac exchange mechanisms. A consistent framework for introducing gluino and neutralino Dirac fields can be designed by extending the N=1 supersymmetry of the MSSM to N=2 in the gauge sector. We examine to which extent like-sign dilepton production in the processes q q -> ~q ~q and e- e- -> ~e- ~e- is affected by the exchange of either Majorana or Dirac gluinos and neutralinos, respectively, at the Large Hadron Collider (LHC) and in the prospective e- e- mode of a lepton linear collider.
We analize the non-cyclic geometric phase for neutrinos. We find that the geometric phase and the total phase associated to the mixing phenomenon provide a tool to distinguish between Dirac and Majorana neutrinos. Our results hold for neutrinos propagating in vacuum and through the matter. Future experiments, based on interferometry, could reveal the nature of neutrinos.
Majorana CP violating phases coming from heavy right-handed Majorana mass matrices ($M_{RR}$) are considered to estimate the masses of neutrinos.The effects of phases on quasi-degenerate neutrinos mass matrix obeying $mu$-$tau$ symmetry predicts the results consistent with observations for (i) solar mixing angle($theta_{12}$) below TBM, (ii) absolute neutrino mass parameters[$m_{ee}$] in neutrinoless double beta ($0 ubetabeta$) decay, and (iii) cosmological upper bound $sum_{i}m_{i}$. Analysis is carried out through parameterization of light left-handed Majorana neutrino matrices $(m_{LL})$ using only two unknown parameters $(epsilon,eta)$ within $mu$-$tau$ symmetry. We consider the charge lepton and up quark matrices as diagonal form of Dirac neutrino mass matrix $(m_{LR})$, and $m_{RR}$ are genrated using $m_{LL}$ through inversion of Type-I seesaw formula. The analysis shows that the masses of neutrinos are in agreement with the upper bound from cosmology and neutrinoless double beta decay. The results presented in this article will have important implications in discriminating the neutrinos mass models.
Nonzero neutrino masses imply the existence of degrees of freedom and interactions beyond those in the Standard Model. A powerful indicator of what these might be is the nature of the massive neutrinos: Dirac fermions versus Majorana fermions. While addressing the nature of neutrinos is often associated with searches for lepton-number violation, there are several other features that distinguish Majorana from Dirac fermions. Here, we compute in great detail the kinematics of the daughters of the decays into charged-leptons and neutrinos of hypothetical heavy neutral leptons at rest. We allow for the decay to be mediated by the most general four-fermion interaction Lagrangian. We demonstrate, for example, that when the daughter charged-leptons have the same flavor or the detector is insensitive to their charges, polarized Majorana-fermion decays have zero forward/backward asymmetry in the direction of the outgoing neutrino (relative to the parent spin), whereas Dirac-fermion decays can have large asymmetries. Going beyond studying forward/backward asymmetries, we also explore the fully-differential width of the three-body decays. It contains a wealth of information not only about the nature of the new fermions but also the nature of the interactions behind their decays.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
