The effects of neutrino oscillations with one mass scale on the atmospheric neutrino flux

1988 ◽  
Vol 209 (2-3) ◽  
pp. 365-372 ◽  
Author(s):  
V. Barger ◽  
K. Whisnant
1999 ◽  
Vol 14 (10n11) ◽  
pp. 689-700 ◽  
Author(s):  
ION STANCU

In this letter we show that the evidence for neutrino oscillations from the super-Kamiokande atmospheric neutrino data fully determines the 3×3 neutrino-oscillations mixing matrix and predicts an energy-independent solar neutrino deficit at the level of 45%. This corresponds to a ratio of measured to predicted neutrino flux of [Formula: see text], in good agreement with the experimental results. We achieve this result within the framework of a minimal, three-generation neutrino mixing, with mass squared differences of ΔM2≃0.45 eV 2 and [Formula: see text]. The mixing matrix derived here is characterized by the mixing angles θ=35.1°, β=5.5° and ψ=23.3°, and a vanishing CP-violating phase, δ=0.


Naturally occurring energetic neutrinos produced by interactions of cosmic rays in the atmosphere produce a signal in deep underground detectors which is a convolution of neutrino flux, neutrino cross section and detection efficiency. The predicted ratio of events induced by v e as compared to v μ is relatively robust (because many sources of uncertainty cancel in the ratio), but it differs significantly from what is observed. Interpretations that involve new physics (e.g. neutrino oscillations or nucleon decay) have been proposed. One interpretation in terms of neutrino oscillations would imply a low value of neutrino-induced upward muons. Although there is no strong evidence for such a deficit, uncertainties in calculating the expected absolute rate prevent one from eliminating this interpretation at present. Precise measurement of muon fluxes at high altitude, as well as calibration of detectors with neutrino beams from accelerators, will help clarify the situation.


2003 ◽  
Vol 18 (08) ◽  
pp. 569-578 ◽  
Author(s):  
MOHAN NARAYAN ◽  
S. UMA SANKAR

We consider three active flavor neutrino oscillations where both the mass-square differences play a role in atmospheric neutrino problem. We calculate the matter effects arising due to propagation through earth. We demonstrate that these effects improve the fit to the electron data vis-a-vis vacuum oscillations but make the fit to the muon data far worse, thus worsening the overall fit. The results of our analytical calculation verify the numerical investigations of this scheme presented earlier by Fogli et al.


1988 ◽  
Vol 61 (14) ◽  
pp. 1537-1540 ◽  
Author(s):  
K. Hidaka ◽  
M. Honda ◽  
S. Midorikawa

2003 ◽  
Vol 18 (12) ◽  
pp. 807-815
Author(s):  
SHEUNG TSUN TSOU ◽  
JONATHAN S. PALMER

We summarize the results showing that all existing data on mixing between up and down fermion states (i.e. CKM matrix and neutrino oscillations) and on the hierarchical quark and lepton mass ratios between generations are consistent with the two phenomena being both consequences of a mass matrix rotating in generation space with changing energy scale. Thus the rotation of the mass matrix can be traced over some 14 orders of magnitude in energy from the mass scale of the t-quark at 175 GeV to below that of the atmospheric neutrino at 0.05 eV.


1994 ◽  
Vol 09 (02) ◽  
pp. 169-179 ◽  
Author(s):  
R. FOOT

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.


1984 ◽  
Vol 30 (1) ◽  
pp. 80-88 ◽  
Author(s):  
G. V. Dass ◽  
K. V. L. Sarma

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