相关论文: Matter Effects in Atmospheric Neutrino Oscillation…
Observations of atmospheric neutrinos by the SuperKamiokande collaboration have demonstrated large mixing of the muon-neutrino. However the present atmospheric neutrino data does not significantly constrain the associated mixing of the…
Atmospheric neutrinos travel very long distances through earth matter. It is expected that the matter effects lead to significant changes in the neutrino survival and oscillation probabilities. Initial analysis of atmospheric neutrino data…
The angular distribution of upward-going muons produced by atmospheric neutrinos in the rock below the MACRO detector show anomalies in good agreement with two flavor neutrino-mu ==> neutrino-tau oscillations with maximum mixing and Delta…
The relevance of the data concerning upward--going muons for the solution of the atmospheric neutrino problem is stressed. In particular, their inclusion in the analysis confirms the goodness of the neutrino oscillation hypothesis and…
New observations with atmospheric neutrinos from the underground experiments SuperKamiokande, Soudan 2, and MACRO, together with earlier results from Kamiokande and IMB, are reviewed. The most recent observations reconfirm aspects of…
That muon neutrinos $\nu_{\mu}$ oscillating into the mixture of tau neutrinos $\nu_{\tau}$ and sterile neutrinos $\nu_{s}$ has been studied to explain the atmospheric $\nu_{\mu}$ disappearance. In this scenario, the effect of Earth matter…
This talk reports the latest indications of an anomaly in the measurements of atmospheric neutrinos. New results from Soudan-2 and Super-Kamiokande provide evidence that the ratio of nu_mu to nu_e interactions is not as expected. High…
Neutrino oscillations change when in media in comparison to vacuum oscillations due to the scattering of neutrinos on matter constituents, electrons particularly. This can be easily described by introducing new effective matter mixing…
With the 1998 announcement of new evidence for muon neutrino disappearance observed by the Super-Kamiokande experiment, the more than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an…
A comprehensive formalism for the description of neutrino oscillations in the Earth in a general scheme with three massive neutrinos and the mass hierarchy m_1<<m_2<<m_3 is presented. Using this formalism, which is valid both in vacuum and…
We compute up-down asymmetries for atmospheric neutrino induced electron and muon events in the SuperKamiokande detector for the following neutrino oscillation models: (A) maximally mixed $\nu_{\mu} - \nu_{\tau}$ or $\nu_{\mu} - \nu_s$, (B)…
When neutrinos propagate in a background, their gravitational couplings are modified by their weak interactions with the particles in the background. In a medium that contains electrons but no muons or taons, the matter-induced…
If neutrino oscillation plays a role in explaining the atmospheric neutrino deficit, then the same phenomenon would necessarily affect also the dark matter indirect-detection signal which consists in a muon-neutrino flux produced by…
New atmospheric neutrino results from Super-Kamiokande are presented. Results from Kamiokande on upward going muons are also presented. All these data, together with the Kamiokande atmospheric neutrino data give evidence for neutrino…
We discuss the possibility to observe matter effects in atmospheric neutrino oscillations. The main conclusion is that an impact on the nu_mu survival probability requires the action of the MSW resonance, which becomes visible for baselines…
We calculate matter effects on neutrino oscillations relevant for long baseline experiments. In particular, we compare the results obtained with constant density along the neutrino path versus results obtained by incorporating the actual…
Observations of atmospheric neutrinos offer compelling evidence that neutrinos have mass and do oscillate. Preliminary data are compatible with maximal $\nu_\mu$--$\nu_\tau$ mixing, but not with pure $\nu_\mu$--$\nu_e$ mixing. In a general…
The simplest explanation for the atmospheric neutrino anomaly is the transition of muon neutrinos and antineutrinos into states of different flavor. Data from the reactor experiment Chooz, and the measurement of the energy and angle…
The apparent anomaly in the ratio of muon to electron atmospheric neutrinos first observed by Kamiokande and IMB has been confirmed by Super-Kamiokande and Soudan-2. The experimental analysis, including the asymmetry in the zenithal…
The neutrinos of long baseline beams travel inside the Earth's crust where the density is approximately rho = 2.8 g cm^-3. If electron neutrinos participate in the oscillations, matter effects will modify the oscillation probabilities with…