Measurement of a small atmospheric ν/ν ratio

Abstract

From an exposure of 25.5 kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electronlike single-ring atmospheric neutrino interactions were detected with momentum p e > 100 MeV/c, p µ > 200 MeV/c, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio (µ/e) DAT A /(µ/e) MC was measured to be 0.61 ± 0.03(stat.) ± 0.05(sys.), consistent with previous results from the Kamiokande, IMB and Soudan-2 experiments, and smaller than expected from theoretical models of atmospheric neutrino production.

LeptonicCPviolation studies at MiniBooNE in the (3+2) sterile neutrino oscillation hypothesis

“…[28]. These constraints include 1489 days of SuperKamiokande charged-current data [9], including the elike and µ-like data samples of sub-and multi-GeV contained events, stopping events, and through-going upgoing muon data events. The analysis in Ref.…”

“…In the standard paradigm of three-active-neutrino mixing occurring at the solar [2,3,4,5,6,7,8] and atmospheric [9,10,11,12,13,14] oscillation scales only, leptonic CP violation would yield different vacuum oscillation probabilities for neutrinos and antineutrinos that could be observed, for example, with accelerator-based neutrino oscillation appearance experiments operating near the atmospheric oscillation maximum [15,16]. This is because CP-odd terms in the oscillation probability formula would appear from solar/atmospheric interference terms involving the single CP-violating Dirac phase appearing in the neutrino mixing matrix [17].…”

Anomalous magnetic moment of muon in 3–3–1 models

“…The SuperKamiokande results [1] confirming non-zero neutrino mass call for the standard model (SM) extension. Among the known extensions, the models based on the SU(3) C ⊗ SU(3) L ⊗ U(1) N gauge group [2,3] have the following intriguing features: firstly, the models are anomaly free only if the number of families N is a multiple of three.…”

“…New gauge bosons in the minimal model are bileptons (Y ± , X ±± ) carrying lepton number L = ±2 and Z ′ . In the 1 On leave from Institute of Physics, NCST, P. O. Box 429, Bo Ho, Hanoi 10000, Vietnam 2 On leave from Department of Physics, Hanoi University of Mining and Geology, Hanoi, Vietnam second model, the bileptons with lepton number L = ±2 are singly-charged Y ± and neutral gauge bosons X 0 , X * 0 , and both are responsible for lepton-number violating interactions.…”

Supernova neutrino–nucleus astrophysics

“…The importance that experiments like mini-BooNE have flow from the increase in reliability and precision in the identification and measurement of neutrino oscillation phenomena in atmospheric neutrinos [12][13][14] and solar neutrinos at Sudbury Neutrino Observatory [15,16], SuperKamiokande [17], Chlorine [18], and Gallium [19][20][21] experiments. These experiments are so restrictive in their definition of the allowed neutrino mixing parameter space that there is "no room" for mixing at an additional δm 2 scale.…”