Search results for "Measurements of neutrino speed"
showing 10 items of 153 documents
The Q-value of tritium β-decay and the neutrino mass
2006
Abstract The paper discusses the influence of β -endpoint energies and related atomic mass values on the determination of the neutrino mass in present and future β -decay experiments with particular emphasis on the case of tritium decay
Status of three-neutrino oscillation parameters
2012
Here we review the current status of global fits to neutrino oscillation data within the three-flavour framework. In our analysis we include the most recent data from solar and atmospheric neutrino experiments as well as the latest results from the long-baseline accelerator neutrino experiments and the recent measurements of reactor neutrino disappearance reported by Double Chooz, Daya Bay and RENO. We present updated determinations for the two neutrino mass splittings and the three mixing angles responsible for neutrino oscillations that, for the first time, have all been measured with 1 sigma accuracies ranging from 3 to 15%. A weak sensitivity for the CP violating phase is also reported …
Matter Effects in Neutrino Propagation
1989
After briefly reviewing the Mikheyev-Smirnov-Wolfenstein effect, I present a particle physics model where the required small neutrino mass arises from spontaneous R parity violation in supergravity theories. It is related to measurable processes associated with the existence of the Majoron and of supersymmetric (SUSY) particles. Astrophysical and laboratory limits tend to exclude regions of oscillation parameters where the high energy neutrinos are adiabatically converted. This suggests the possibility of a large reduction in the pp and 7 Be neutrino flux even for a mildly reduced 8 B neutrino flux, thus stressing the importance of the gallium experiments. Finally I consider other types of …
Precise predictions for Dirac neutrino mixing
2016
The neutrino mixing parameters are thoroughly studied using renormalization-group evolution of Dirac neutrinos with recently proposed parametrization of the neutrino mixing angles referred as `high-scale mixing relations'. The correlations among all neutrino mixing and $CP$ violating observables are investigated. The predictions for the neutrino mixing angle $\theta_{23}$ are precise, and could be easily tested by ongoing and future experiments. We observe that the high scale mixing unification hypothesis is incompatible with Dirac neutrinos due to updated experimental data.
Can we probe intrinsic CP and T violations and nonunitarity at long baseline accelerator experiments?
2017
One of the fundamental parameters entering the neutrino oscillation framework is the leptonic $CP$ phase ${\ensuremath{\delta}}_{13}$, and its measurement is an important goal of the planned long baseline experiments. It should be noted that ordinary matter effects complicate the determination of this parameter, and there are studies in the literature that deal with separation of intrinsic vs extrinsic $CP$ violation. It is important to investigate the consequences of new physics effects that can not only hamper the measurement of ${\ensuremath{\delta}}_{13}$ but also impact the consequences of discrete symmetries such as $CP$, $T$, and unitarity in different oscillation channels. In the pr…
The antares neutrino detector instrumentation
2012
ANTARES is actually the fully operational and the largest neutrino telescope in the Northern hemisphere. Located in the Mediterranean Sea, it consists of a 3D array of 885 photomultiplier tubes (PMTs) arranged in 12 detection lines (25 storeys each), able to detect the Cherenkov light induced by upgoing relativistic muons produced in the interaction of high energy cosmic neutrinos with the detector surroundings. Among its physics goals, the search for neutrino astrophysical sources and the indirect detection of dark matter particles coming from the sun are of particular interest. To reach these goals, good accuracy in track reconstruction is mandatory, so several calibration systems for tim…
Status of the neutrino telescope AMANDA: Monopoles and WIMPs
2001
The neutrino telescope AMANDA has been set up at the geographical South Pole as first step to a neutrino telescope of the scale of one cubic kilometer, which is the canonical size for a detector sensitive to neutrinos from Active Galactic Nuclei (AGN), Gamma Ray Bursts (GRB) and Topological Defects (TD). The location and depth in which the detector is installed is given by the requirement to detect neutrinos by the Cherenkov light produced by their reaction products and to keep the background due to atmospheric muons as small as possible. However, a detector optimized for this purpose is also capable to detect the bright Cherenkov light from relativistic Monopoles and neutrino signals from …
Indirect searches for Dark Matter with the ANTARES neutrino telescope
2012
The results of a search for high-energy neutrinos coming from the direction of the Sun using the data recorded by the ANTARES neutrino telescope during 2007 and 2008 are presented. The number of neutrinos observed is found to be compatible with background expectations and upper limits for the spin-dependent and spin-independent WIMP-proton cross-sections are derived and compared to predictions of the CMSSM. These limits are comparable to those obtained by other neutrino telescopes and are more stringent than those obtained by direct search experiments for the spin-dependent WIMP-proton cross-section assuming the self-annihilation proceeds through hard channels, i.e. via W + W and t + t .
Status of the IceCube Neutrino Observatory
2004
Abstract The IceCube neutrino telescope, to be constructed near the Antarctic South Pole, represents the next generation of neutrino telescope. Its large 1 km3 size will make it uniquely sensitive to the detection of neutrinos from astrophysical sources. The current design of the detector is presented. The basic performance of the detector and its ability to search for neutrinos from various astrophysical sources has been studied using detailed simulations and is discussed.
Effects of degenerate sterile neutrinos on the supernova neutrino flux
2004
We consider the possibility that there exist sterile neutrinos which are closely degenerate in mass with the active neutrinos and mixed with them. We investigate the effects of this kind of active-sterile neutrino mixing on the composition of supernova neutrino flux at the Earth. If an adiabatic MSW-transition between active and sterile neutrinos takes place, it could dramatically diminish the electron neutrino flux.