scholarly journals Accelerator, Reactor and Atmospheric Neutrino Data: A Three-Flavor Oscillation Analysis

1997 ◽  
Vol 12 (04) ◽  
pp. 781-799 ◽  
Author(s):  
Srubabati Goswami ◽  
Amitava Raychaudhuri ◽  
Kamales Kar
Keyword(s):  
Experimental Data ◽  
Narrow Range ◽  
Atmospheric Neutrino ◽  
Mass Scale ◽  
Atmospheric Neutrinos ◽  
Mixing Angles ◽  
Oscillation Analysis ◽  
Reactor Neutrinos ◽  
Flavor Oscillation ◽  
Interesting Solution

We perform a three-flavor oscillation analysis of accelerator, reactor and atmospheric neutrino results. Motivated by the experimental data, the mass squared differences are chosen to be Δ12 = Δ13 in the range 0.5–10 eV2 and Δ23 = 10-2 eV2. In such a scenario, the oscillation probabilities for the accelerator and reactor neutrinos involve only two of the mixing angles and one mass scale. But the atmospheric neutrino oscillation is governed by both mass scales and all the three mixing angles. The greater latitude allowed by the scheme leads to some new and interesting solution regions for atmospheric neutrinos in addition to the two-flavor limits usually discussed. However, incorporating the constraints from the previous accelerator searches for neutrino oscillations, a very narrow range of allowed mixing angles survives. This zone is beyond the reach of the on-going accelerator experiments CHORUS and NOMAD with their projected sensitivity.

RECENT RESULTS FROM K2K

2002 ◽  
Vol 17 (24) ◽  
pp. 3364-3377 ◽  
Author(s):  
◽  
C. K. JUNG
Keyword(s):  
Neutrino Oscillation ◽  
Atmospheric Neutrino ◽  
Neutrino Beam ◽  
Statistical Fluctuation ◽  
Atmospheric Neutrinos ◽  
Long Baseline ◽  
Neutrino Oscillation Experiment ◽  
Oscillation Analysis ◽  
The Us ◽  
Oscillation Experiment

K2K is a long baseline neutrino oscillation experiment using a neutrino beam produced at the KEK 12 GeV PS, a near detector complex at KEK and a far detector (Super-Kamiokande) in Kamioka, Japan. The experiment was constructed and is being operated by an international consortium of institutions from Japan, Korea, and the US. The experiment started taking data in 1999 and has successfully taken data for about two years. K2K is the first long beseline neutrino oscillation experiment with a baseline of order hundreds of km and is the first accelerator based neutrino oscillation experiment that is sensitive to the Super-Kamiokande allowed region obtained from the atmospheric neutrino oscillation analysis. A total of 44 events have been observed in the far detector during the period of June 1999 to April 2001 corresponding to 3.85 × 1019 protons on target. The observation is consistent with the neutrino oscillation expectations based on the oscillation parameters derived from the atmospheric neutrinos, and the probability that this is a statistical fluctuation of non-oscillation expectation of [Formula: see text] is less than 3%.

WHAT DOES μ - τ SYMMETRY IMPLY ABOUT LEPTONIC CP VIOLATION?

2007 ◽  
Vol 16 (05) ◽  
pp. 1373-1381 ◽  
Author(s):  
TEPPEI BABA
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Symmetry Breaking ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Difference ◽  
Atmospheric Neutrino ◽  
Symmetric Part ◽  
Neutrino Mixing ◽  
Mixing Angles

The μ - τ symmetry can reproduce the consistent results with experimental data of θ13, and θ23 (θ13, and θ23 respectively denote the νe - ντ, and νμ - ντ, mixing angles). However, we can not address the issue of the leptonic CP violation in μ - τ symmetric models. So we add the μ - τ symmetry breaking part to include the CP violation. We characterize leptonic CP violation in terms of three phases, where one is conventional phase δ and others are additional phases ρ and γ. These δ, ρ and γ are, respectively, the phases of νe - ντ, νe - νμ and νμ - ντ mixings. The ρ and γ are redundant but the effect of ρ remains in the leptonic CP violation which is characterized by δ + ρ. The δ arises from the μ - τ symmetry breaking part of the Meμ and Meτ while ρ arises from of μ - τ symmetric part of the Meμ and Meτ, where Mij stands for ij (i,j = e,μ,τ) element of M(= [Formula: see text] for Mν being a flavor neutrino mass matrix). Moreover, θ23 can be exactly estimated to be: [Formula: see text] ( sin θ ∝ sin θ13 cos (δ + ρ)[Formula: see text], sin ϕ ∝ Mμμ - Mττ, where [Formula: see text] is the solar neutrino mass difference squared). The conditions of maximal atmospheric neutrino mixing are given by [Formula: see text] and Mμμ = Mττ,which indicate maximal Dirac CP violation.

scholarly journals Highlight Talk from Super-Kamiokande

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 20
Author(s):  
Yuuki Nakano ◽  
On behalf of the Super-Kamiokande Collaboration
Keyword(s):  
Dark Matter ◽  
Energy Spectrum ◽  
Atmospheric Neutrino ◽  
Solar Neutrinos ◽  
Mass Hierarchy ◽  
Cherenkov Detector ◽  
Oscillation Analysis ◽  
Water Cherenkov Detector ◽  
Flavor Oscillation ◽  
Future Project

Super-Kamiokande (SK), a 50 kton water Cherenkov detector in Japan, is observing both atmospheric and solar neutrinos. It is also searching for supernova (relic) neutrinos, proton decays and dark matter-like particles. A three-flavor oscillation analysis was conducted with the atmospheric neutrino data to study the mass hierarchy, the leptonic CP violation term, and other oscillation parameters. In addition, the observation of solar neutrinos gives precise measurements of the energy spectrum and oscillation parameters. In this proceedings, we given an overview of the latest results from SK and the prospect toward the future project of SK-Gd.

scholarly journals NEUTRINO OSCILLATIONS AND THE EXACT PARITY MODEL

1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT
Keyword(s):  
Neutrino Mass ◽  
General Result ◽  
Neutrino Oscillations ◽  
Mass Matrix ◽  
Atmospheric Neutrino ◽  
Solar Neutrinos ◽  
Specific Model ◽  
Neutrino Mixing ◽  
Mixing Angles ◽  
Significant Deficit

We re-examine neutrino oscillations in exact parity models. Previously it was shown in a specific model that large neutrino mixing angles result. We show here that this is a general result of neutrino mixing in exact parity models provided that the neutrino mass matrix is real. In this case, the effects of neutrino mixing in exact parity models is such that the probability of a given weak eigenstate remaining in that eigenstate averages to less than half when averaged over many oscillations. This result is interesting in view of the accumulating evidence for a significant deficit in the number of solar neutrinos. It may also be of relevance to the atmospheric neutrino anomaly.

scholarly journals Improving the prediction of the Atmospheric neutrino flux using the atmospheric muon flux

2019 ◽  
Vol 208 ◽  
pp. 07001
Author(s):  
Morihiro Honda
Keyword(s):  
Energy Range ◽  
Energy Region ◽  
Test Bench ◽  
Atmospheric Neutrino ◽  
Neutrino Flux ◽  
Interaction Model ◽  
Muon Flux ◽  
Atmospheric Neutrinos ◽  
Hadronic Interaction ◽  
Atmospheric Muon

It is well known that the correlation of atmospheric neutrinos and muons are simply correlated in the energy region of 1–10 GeV, and used for the test bench of the hadronic interaction model used for the calculation of the atmospheric neutrino flux. However, the correlation becomes unclear for neutrinos in the energy range below 1 GeV, which is important for the study of mass ordering of neutrino and CP phase of the neutrino mass. We extend the study of the correlation to the lower neutrino energies and find that the atmospheric muon flux observed at high altitude shows a good correlation to the atmospheric neutrino flux, and could be used to calibrate the hadronic interaction model.

scholarly journals Atmospheric Neutrinos

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Takaaki Kajita
Keyword(s):  
Atmospheric Neutrino ◽  
Decay Chain ◽  
Muon Neutrinos ◽  
Atmospheric Neutrinos ◽  
Electron Neutrinos ◽  
Tau Neutrinos ◽  
Decay Products ◽  
Charged Pions ◽  
Neutrino Experiments ◽  
Energy Dependent

Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

scholarly journals ON FERMION MASS HIERARCHY WITH EXTRA DIMENSIONS

2000 ◽  
Vol 15 (01) ◽  
pp. 29-39 ◽  
Author(s):  
KOICHI YOSHIOKA
Keyword(s):  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Atmospheric Neutrino ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angles ◽  
Four Dimensions ◽  
Matter Fields ◽  
Neutrino Masses And Mixings

Recently, various phenomenological implications of the existence of extra space–time dimensions have been investigated. In this letter, we construct a model with realistic fermion mass hierarchy with (large) extra dimensions beyond the usual four dimensions. In this model, it is assumed that some matter fields live in the bulk and the others are confined to our four-dimensional wall. It can naturally reproduce the quark and lepton mass hierarchy and mixing angles without any symmetry arguments. We also discuss some possibilities of obtaining suitable neutrino masses and mixings for the solar and atmospheric neutrino problems.

scholarly journals Constraints onθ13from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND

2011 ◽  
Vol 83 (5) ◽  
Author(s):  
A. Gando ◽  
Y. Gando ◽  
K. Ichimura ◽  
H. Ikeda ◽  
K. Inoue ◽  
...  
Keyword(s):  
Oscillation Analysis ◽  
Flavor Oscillation
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