Limits on different majoron decay modes of 100Mo and 82Se for neutrinoless double beta decays in the NEMO-3 experiment

The NEMO-3 tracking detector is located in the Fréjus Underground Laboratory. It was designed to study double beta decay in a number of different isotopes. Presented here are the experimental half-life limits on the double beta decay process for the isotopes 100Mo and 82Se for different majoron emission modes and limits on the effective neutrino–majoron coupling constants. In particular, new limits on “ordinary” majoron (spectral index 1) decay of 100Mo (T1/2>2.7×1022 yr) and 82Se (T1/2>1.5×1022 yr) have been obtained. Corresponding bounds on the majoron–neutrino coupling constant are gee<(0.4–1.8)×10−4 and <(0.66–1.9)×10−4

Effects of architectural issues on a km3 scale detector

Simulation results showing the comparison between the performance of different km3 detector geometries are reported. Effective neutrino areas and angular resolutions are reported for three different geometries based on NEMO-towers and strings. The results show that the NEMO-tower based detector has the best performance concerning both the effective area and the angular resolution isotropyComment: to be published on VVVNT2 proceedings (Catania, Italy, November 8-11, 2005

Short Term and Long Term Bioacoustic Monitoring of the Marine Environment. Results from NEMO ONDE Experiment and Way Ahead.

The INFN NEMO-OνDE (Ocean Noise Detection Experiment) station, deployed on the seafloor at 2000 m depth 25 km offshore Catania (Sicily, Italy) in year 2005, was designed to continuously transmit broad-band acoustic data through optical cables to the INFN lab located in the port of Catania. It was operational until November 2006, when it was replaced by other experimental equipment. During the operational period, 5 minutes of recording (4 hydrophones, 45 kHz bandwidth, 96 kHz sampling rate at 24 bits resolution) were taken every hour. The experiment provided long-term data on the underwater noise and an unique opportunity to study the acoustic emissions of marine mammals living in, or transiting through the area east of Sicily. The recordings revealed a more frequent and consistent presence of sperm whales than previously believed

High sensitivity GEM experiment on double beta decay of 76-Ge

The GEM project is designed for the next generation 2 beta decay experiments with 76-Ge. One ton of ''naked'' HP Ge detectors (natural at the first GEM-I phase and enriched in 76-Ge to 86% at the second GEM-II stage) are operating in super-high purity liquid nitrogen contained in the Cu vacuum cryostat (sphere with diameter 5 m). The latest is placed in the water shield. Monte Carlo simulation evidently shows that sensitivity of the experiment (in terms of the T1/2 limit for neutrinoless 2 beta decay) is 10^27 yr with natural HP Ge crystals and 10^28 yr with enriched ones. These bounds corresponds to the restrictions on the neutrino mass less than 0.05 eV and 0.015 eV with natural and enriched detectors, respectively. Besides, the GEM-I set up could advance the current best limits on the existence of neutralinos - as dark matter candidates - by three order of magnitudes, and at the same time would be able to identify unambiguously the dark matter signal by detection of its seasonal modulation.Comment: LaTeX, 20 pages, 4 figure

Revisiting Bimaximal Neutrino Mixing in a Model with S4 Discrete Symmetry

In view of the fact that the data on neutrino mixing are still compatible with a situation where Bimaximal mixing is valid in first approximation and it is then corrected by terms of order of the Cabibbo angle, arising from the diagonalization of the charged lepton masses, we construct a model based on the discrete group S4 where those properties are naturally realized. The model is supersymmetric in 4-dimensions and the complete flavour group is S4 x Z4 x U(1)_FN, which also allows to reproduce the hierarchy of the charged lepton spectrum. The only fine tuning needed in the model is to reproduce the small observed value of r, the ratio between the neutrino mass squared differences. Once the relevant parameters are set to accommodate r then the spectrum of light neutrinos shows a moderate normal hierarchy and is compatible, within large ambiguities, with the constraints from leptogenesis as an explanation of the baryon asymmetry in the Universe.Comment: 30 pages, 5 figures; added reference

Status of the NEMO project

Activities leading to the realization of a km3 Cherenkov neutrino detector, carried out by the NEMO collaboration, are described. Long term exploration of a 3500 m deep site in the Mediterranean close to the Sicilian coast has shown that it is optimal for the installation of the detector. A complete feasibility study, which has considered all the components of the detector, as well as its deployment, has been carried out demonstrating that technological solutions exist for the realization of the km3 detector. The realization of a technological demonstrator (the NEMO Phase 1 project) is under way

Status of NEMO

The activities towards the realization of an underwater km3 Čerenkov neutrino detector carried out by the NEMO Collaboration are described. Long term exploration of a 3500 m deep sea site close to the Sicilian coast has shown that it is optimal for the installation of the detector. The realization of a Phase-1 project, which is under way, will validate the proposed technologies for the realization of the km3 detector on a Test Site at 2000 m depth. The realization of a new infrastructure on the candidate site (Phase-2 project) will provide the possibility to test detector components at 3500 m depth

The neutrino Mediterranean observatory project

Activities leading to the realization of a km3 Cherenkov neutrino detector, carried out by the NEMO collabo- ration, are described. Long term exploration of a 3500 m deep site in the Mediterranean close to the Sicilian coast has shown that it is optimal for the installation of the detector. A complete feasibility study, that has considered all the components of the detector as well as its deployment, has been carried out demonstrating that technological solutions exist for the realization of the km3 detector. The realization of a technological demonstrator (the NEMO Phase 1 project) is under way