652 research outputs found
A High Statistics Search for Electron-Neutrino --> Tau-Neutrino Oscillations
We present new limits on nu_e to nu_tau and nu_e to nu_sterile oscillations
by searching for electron neutrino dissappearance in the high-energy wide-band
CCFR neutrino beam. Sensitivity to nu_tau appearance comes from tau decay modes
in which a large fraction of the energy deposited is electromagnetic. The beam
is composed primarily of muon neutrinos but this analysis uses the 2.3%
electron neutrino component of the beam. Electron neutrino energies range from
30 to 600 GeV and flight lengths vary from 0.9 to 1.4 km. This limit improves
the sensitivity of existing limits and obtains a lowest 90% confidence upper
limit in sin**2(2*alpha) of 9.9 x 10**(-2) at delta-m**2 of 125 eV**2.Comment: submitted to Phys. Rev. D. Rapid Com
A new ordering principle for the classical statistical analysis of Poisson processes with background
Inspired by the recent proposal by Feldman and Cousins of a ``unified
approach to the classical statistical analysis of small signals'' based on a
choice of ordering in Neyman's construction of classical confidence intervals,
I propose a new ordering principle for the classical statistical analysis of
Poisson processes with background which minimizes the effect on the resulting
confidence intervals of the observation of less background events than
expected. The new ordering principle is applied to the calculation of the
confidence region implied by the recent null result of the KARMEN neutrino
oscillation experiment.Comment: 16 pages including 5 figures, RevTeX. Final version published in
Phys. Rev. D 59 (1999) 05300
Statistical Analysis of Different Muon-antineutrino->Electron-antineutrino Searches
A combined statistical analysis of the experimental results of the LSND and
KARMEN \numubnueb oscillation search is presented. LSND has evidence for
neutrino oscillations that is not confirmed by the KARMEN experiment. This
joint analysis is based on the final likelihood results for both data sets. A
frequentist approach is applied to deduce confidence regions. At a combined
confidence level of 36%, there is no area of oscillation parameters compatible
with both experiments. For the complementary confidence of 1-0.36=64%, there
are two well defined regions of oscillation parameters (sin^2(2th),Dm^2)
compatible with both experiments.Comment: 25 pages, including 10 figures, submitted to Phys. Rev.
A Search for Muon-neutrino to Electron-neutrino and Muon-antineutrino to Electron-antineutrino Oscillations at NuTeV
Limits on and oscillations
are extracted using the NuTeV detector with sign-selected and
\nub_\mu beams. In \nub_\mu mode, for the case of ,
is excluded, and for
, . The NuTeV data exclude the
high end of oscillations parameters
favored by the LSND experiment without the need to assume that the oscillation
parameters for and \nub are the same. We present the most stringent
experimental limits for
oscillations in the large region.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. Letters, UR-164
Experimental search for the LSND anomaly with the ICARUS detector in the CNGS neutrino beam
We report an early result from the ICARUS experiment on the search for nu_mu
to nu_e signal due to the LSND anomaly. The search was performed with the
ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS
neutrinos from CERN at an average energy of about 20 GeV, after a flight path
of about 730 km. The LSND anomaly would manifest as an excess of nu_e events,
characterized by a fast energy oscillation averaging approximately to
sin^2(1.27 Dm^2_new L/ E_nu) = 1/2. The present analysis is based on 1091
neutrino events, which are about 50% of the ICARUS data collected in 2010-2011.
Two clear nu_e events have been found, compared with the expectation of 3.7 +/-
0.6 events from conventional sources. Within the range of our observations,
this result is compatible with the absence of a LSND anomaly. At 90% and 99%
confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation
probabilities of 5.4 10^-3 and 1.1 10^-2 are set respectively. The result
strongly limits the window of open options for the LSND anomaly to a narrow
region around (Dm^2, sin^2(2 theta))_new = (0.5 eV^2, 0.005), where there is an
overall agreement (90% CL) between the present ICARUS limit, the published
limits of KARMEN and the published positive signals of LSND and MiniBooNE
Collaborations.Comment: 10 pages, 7 figure
New interactions in neutrino oscillations with three light flavors
If one assumes solar and LSND neutrino oscillations to explain the
corresponding data, then the atmospheric neutrino deficit cannot be
accommodated within the Standard Model with three light flavors, unless one
ignores the data's zenith-angle dependence. We propose a novel solution to this
problem by postulating large anomalous diagonal -quark interactions
which affect oscillations traversing the Earth and induce
the observed zenith-angle dependence.Comment: Final version, to appear in Phys. Rev. Letters dated May 25, 199
Hierarchical Four-Neutrino Oscillations With a Decay Option
We present a new and novel synthesis of all existing neutrino data regarding
the disappearance and appearance of and . We assume four
neutrinos: , as well as a heavier singlet neutrino
of a few eV. The latter may decay into a massless Goldstone boson (the
singlet Majoron) and a linear combination of the doublet antineutrinos. We
comment on how this scenario may be verified or falsified in future
experiments.Comment: 13 pages, no figur
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