13 research outputs found
Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2
We have searched for the proton decay mode proton to neutrino K+ using the
one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained
from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for
occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0.
We found one candidate event consistent with background, yielding a limit,
tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters
The Atmospheric neutrino flavor ratio from a 3.9 fiducial kiloton year exposure of Soudan-2
We report a measurement of the atmospheric neutrino flavor ratio, R, using a
sample of quasi-elastic neutrino interactions occurring in an iron medium. The
flavor ratio (tracks/showers) of atmospheric neutrinos in a 3.9 fiducial
kiloton-year exposure of Soudan 2 is 0.64 +- 0.11 (stat.) +- 0.06 (syst.) of
that expected. Important aspects of our main analysis have been checked by
carrying out two independent, alternative analyses; one is based upon automated
scanning, the other uses a multivariate approach for background subtraction.
Similar results are found by all three approaches.Comment: 15 pages, 4 figures. To be published in Physics Letters
Measurement of the atmospheric neutrino flavor composition in Soudan-2
The atmospheric neutrino flavour ratio measured using a 1.52 kton-year
exposure of Soudan 2 is found to be 0.72 +- 0.19 +0.05 -0.07 relative to the
expected value from a Monte Carlo calculation. The possible background of
interactions of neutrons and photons produced in muon interactions in the rock
surrounding the detector has been investigated and is shown not to produce low
values of the ratio.Comment: 18 pages, LaTeX, 3 ps files, and 2 style files. Submitted to Physics
Letter
The magnetized steel and scintillator calorimeters of the MINOS experiment
The Main Injector Neutrino Oscillation Search (MINOS) experiment uses an accelerator-produced neutrino beam to perform precision measurements of the neutrino oscillation parameters in the "atmospheric neutrino" sector associated with muon neutrino disappearance. This long-baseline experiment measures neutrino interactions in Fermilab's NuMI neutrino beam with a near detector at Fermilab and again 735 km downstream with a far detector in the Soudan Underground Laboratory in northern Minnesota. The two detectors are magnetized steel-scintillator tracking calorimeters. They are designed to be as similar as possible in order to ensure that differences in detector response have minimal impact on the comparisons of event rates, energy spectra and topologies that are essential to MINOS measurements of oscillation parameters. The design, construction, calibration and performance of the far and near detectors are described in this paper. © 2008 Elsevier B.V