3 research outputs found
Lepton Number Violation in TeV Scale See-Saw Extensions of the Standard Model
The low-energy neutrino physics constraints on the TeV scale type I see-saw
scenarios of neutrino mass generation are revisited. It is shown that lepton
charge (L) violation, associated to the production and decays of heavy Majorana
neutrinos N_{j} having masses in the range of M_j \sim (100 \div 1000) GeV and
present in such scenarios, is hardly to be observed at ongoing and future
particle accelerator experiments, LHC included, because of very strong
constraints on the parameters and couplings responsible for the corresponding
|\Delta L| = 2 processes. If the heavy Majorana neutrinos N_j are observed and
they are associated only with the type I mechanism, they will behave
effectively like pseudo-Dirac fermions. Conversely, the observation of effects
proving the Majorana nature of N_j would imply that these heavy neutrinos have
additional relatively strong couplings to the Standard Model particles or that
light neutrino masses compatible with the observations are generated by a
mechanism other than see-saw (e.g., radiatively at one or two loop level) in
which the heavy Majorana neutrinos N_j are nevertheless involved.Comment: Contribution to the Proceedings of DISCRETE 2010- Symposium on
Prospects in the Physics of Discrete Symmetries, 8 page
Unity of CP and T Violation in Neutrino Oscillations
In a previous work a simultaneous P- CP[P] and P- T[P] bi-probability plot
was proposed as a useful tool for unified graphical description of CP and T
violation in neutrino oscillation. The ``baseball diamond'' structure of the
plot is understood as a consequence of the approximate CP-CP and the T-CP
relations obeyed by the oscillation probabilities. In this paper, we make a
step forward toward deeper understanding of the unified graphical
representation by showing that these two relations are identical in its
content, suggesting a truly unifying view of CP and T violation in neutrino
oscillations. We suspect that the unity reflects the underlying CPT theorem. We
also present calculation of corrections to the CP-CP and the T-CP relations to
leading order in Delta m^2_{21} / Delta m^2_{31} and s^2_{13}.Comment: 20 references added, version to appear in "Focus Issue on Neutrino
Physics" of New Journal of Physic
Majorana Neutrino Mixing
The most plausible see-saw explanation of the smallness of the neutrino
masses is based on the assumption that total lepton number is violated at a
large scale and neutrinos with definite masses are Majorana particles. In this
review we consider in details difference between Dirac and Majorana neutrino
mixing and possibilities of revealing Majorana nature of neutrinos with
definite masses