[en] This review is organised as follows. It shall start with describing the existing underground facilities. It shall be discussed the basic concepts of neutrino mixing and neutrino oscillations and summarise the present experimental evidence. This evidence comes mainly from experiments, in underground laboratories, on neutrinos from the Sun (solar neutrinos) and neutrinos indirectly produced by cosmic rays in the atmosphere (atmospheric neutrinos). Further important pieces of information are due to experiments on electron antineutrinos from reactors (CHOOZ) and on muon neutrinos from an accelerator (K2K). Then it shall be discussed the concept of neutrino masses and how different experiments (single-and double-beta decay, Supernova neutrinos, Cosmology) measure different combinations of the three mass eigenvalues. This issue is directly connected with the unknown nature of neutrinos: Dirac or Majorana particles? In the following sections shall be reviewed the contributions given by the Gran Sasso Laboratory and discussed the possible research program for the next years

[en] It is argued that the observed deficit of solar and atmospheric neutrinos can be explained by neutrino oscillations ν_e → ν_s and ν_μ → ν'_s involving two hypothetic sterile neutrinos ν_s and ν'_s (blind to all Standard-Model interactions). They are keen to mix nearly maximally with ν_e and ν_μ, respectively, to form neutrino mass states ν_l, ν₄ and ν₂, ν₅. Our argument is presented in the framework of a model of fermion ''texture'' formulated previously, which implies the existence of two sterile neutrinos beside the three conventional. (author)

[en] This thesis presents a study of the capability of the proposed MINOS long-baseline neutrino experiment to measure the neutrino mixing parameters, if oscillations are assumed to occur with the parameters suggested by the results of atmospheric neutrino experiments. It is shown that the observation of a neutrino energy dependent suppression of ν_μ events in MINOS could provide a measurement of the mixing parameters to greater than 10% accuracy for 0.005 < Δm² < 0.2 eV² if sin² 2θ ≥ 0.7. The performance of a putative low energy beam for MINOS has been studied and it is shown that this beam could allow neutrino oscillations to be observed in MINOS above Δm² = 0.002 eV² . An independent and complementary method to measure the mixing parameters by using the energy distributions of ν_e CC events is also presented. A test has been developed that is sensitive to ν_μ → ν_τ oscillations in MINOS by searching for event topologies that are characteristic of tau leptons. The sensitivity of the test to neutrino oscillations has been evaluated for a variety of possible detector configurations of the MINOS far detector. A fine grained detector (2 cm steel plates and 2 cm transverse pitch) is shown to provide the greatest sensitivity; a limit of sin² 2θ < 0.2 could be set at 90% confidence at large Δm² for a 20 kiloton year exposure of MINOS. A five standard deviation effect or greater could be observed if ν_μ → ν_τ oscillations occur with sin² 2θ = 1 and Δm² ≥ 10^-2 eV². The prospects of analysing MINOS data in the framework of three-flavour neutrino oscillations have been assessed and a preliminary Monte Carlo analysis in three-generations is presented. The results of the CHOOZ reactor neutrino experiment and the solar neutrino experiments are shown to rule out the possibility of observing a large CP violating amplitude in MINOS. Finally it is shown how the future results of MINOS are complementary to other searches for neutrino oscillations. (author)

[en] The primary goal of the OPERA long-baseline neutrino oscillation experiment is the first direct detection of ν_μ →ν_τ oscillations. The hybrid OPERA detector consists of a target made from lead and photo emulsions, providing micrometric resolution, and electronic detector parts for on-line readout. It is located in the LNGS underground laboratory, at a baseline of 730 km from the SPS at CERN, where the ν_μ CNGS beam is produced. The measurement of ν_τ appearance relies on the detection of the decay of τ leptons which are created in ν_τ charged current reactions. Data acquisition started in 2008, and numerous beam-induced events have been recorded, including the observation of a first ν_τ candidate event in 2009. In this talk, the current status of the oscillation analysis is presented.

[en] Neutrinos play an exceptional role as well in particle or nuclear physics as in astrophysics. The purpose of the conference is to cover the main steps of their history since the brilliant and inspired idea of Pauli in December 1930. Trying to cover all the facets of this fascinating particles, the presentations are parted into 5 topics: -) invention of a new particle, -) natural neutrinos and interdisciplinary aspects, -) man-made sources of neutrinos, -) quantum mechanics at work: oscillations and particle physics, -) neutrinos and fundamental particle physics, and -) neutrinos as messengers of the universe. The objective is, for each topic, to have a historian/historical approach and follow as close as possible the original papers in correlation with the scientific and historical context. This document is composed of the slides of the presentations and of a few posters

[en] The possible outcomes of neutrino events at both Super-Kamiokande and SNO for a type-II supernova are analyzed considering the uncertainties in supernova neutrino spectra (temperature) at emission, which may complicate the interpretation of the observed events. With the input of parameters deduced from the current solar and atmospheric experiments, the consequences of direct-mass hierarchy m_ντ>>m_νμ>m_νe and inverted-mass hierarchy m_νe>m_νμ>>m_ντ are investigated. Even if the ν temperatures are not precisely known, we find that future experiments are likely to be able to separate the currently accepted solutions to the solar neutrino problem, large-angle Mikheyev-Smirnov-Wolfenstein (MSW), small-angle MSW, and the vacuum oscillation, as well as to distinguish between the direct and inverted mass hierarchies of the neutrinos. (c) 2000 The American Physical Society

[en] Limits on ν_μ→ν_e and ν_μ→ν_e oscillations are extracted using the NuTeV detector with sign-selected ν_μ and ν_μ beams. In ν_μ mode, for the case of sin²2α=1 , Δm²>2.6 eV ² is excluded, and for Δm²>>1000 eV² , sin²2α>1.1x10^-3 . The NuTeV data exclude the high Δm² end of ν_μ→ν_e oscillation parameters favored by the LSND experiment without the need to assume that the oscillation parameters for ν and ν are the same. We present the most stringent experimental limits for ν_μ(ν_μ)→ν_e(ν_e) oscillations in the large Δm² region

[en] Supernova (SN) explosions are the place of very fundamental phenomena, whose privileged messengers are neutrinos. But such events are very rare. Then, SN detection has to be combined with other purposes. The recent developments of SN detectors have been associated with developments of underground particle physics (proton decay, monopoles ...). But here, I will restrict myself to discuss the possibilities for a supernova detector to be sensitive to other sources of neutrinos, astrophysical or terrestrial

[en] Neutrino oscillation experiments (ν_μ → ν_e and ν_μ → → ν_τ) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author)

[en] Full text: Neutrino oscillations, the changing of neutrino flavour state from one of τ, μ or e, to another, are proof of massive neutrinos, in turn pointing to Physics beyond the Standard Model, and so are of great current interest. Solar and atmospheric neutrino results suggested evidence for neutrino oscillations. Further, a tau neutrino mass of ∼ 10 eV could supply the missing mass needed to close the Universe. To satisfy the increasing interest, CERN's Neutrino Physics Program commissioned two concurrent experiments to investigate the possibility of neutrino oscillations, one of which is NOMAD, Neutrino Oscillation Magnetic Detector. NOMAD was designed to verify or deny the earlier positive neutrino oscillations results by searching for muon to tauon neutrino oscillations in accelerator neutrinos. The LSND experiment later provided evidence for muon to electron neutrino oscillations, but due to the multi-purpose design of NOMAD, it was also possible to investigate this channel. Moreover, the area of phase space being uncovered, (related to neutrino energy and oscillation length), overlaps considerably with that of LSND. An electron neutrino oscillation search involves looking for electron neutrinos in what is primarily a muon neutrino beam, with just a small contamination of electron neutrinos. It is surmised that the excess of electron neutrinos come from oscillated muon neutrinos. This type of search is called an appearance search. The principles of such a search will be detailed herein. These include a breakdown of the CERN Neutrino Beam and a method for detecting and collating different neutrino flavours at NOMAD