40 research outputs found
New Results from the MINOS Experiment - EPS 2011 conference proceedings
The MINOS experiment is a long-baseline neutrino experiment designed to study
neutrino behaviour, in particular the phenomenon of neutrino oscillations.
MINOS sends the NuMI neutrino beam through two detectors, a Near Detector 1 km
downstream from the beam source at Fermilab, and a Far Detector 735 km away in
the Soudan Mine in Minnesota. MINOS has been taking beam data since 2005. This
document summarises recent neutrino oscillations results, with particular
emphasis on electron neutrino appearance, which probes the angle
of the neutrino mass mixing matrix. For an exposure of 8.2
protons on target, MINOS finds that for the
normal mass hierarchy, and for the inverted mass hierarchy at the 90%
C.L., if the CP-violating phase .Comment: EPS Conference Proceeding
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
New results for muon neutrino to electron neutrino oscillations in the MINOS experiment
MINOS is a long-baseline neutrino oscillation experiment situated along Fermilab's high-intensity NuMI neutrino beam. MINOS has completed an updated search for muon neutrino to electron neutrino transitions, observation of which would indicate a non-zero value for the neutrino mixing angle theta_13. The present 7x1020 protons-on-target data set represents more than double the exposure used in the previous analysis.
The new result and its implications are presented
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Electron Neutrino Appearance in the MINOS Experiment
The MINOS experiment is a long-baseline neutrino oscillation experiment which sends a high intensity muon neutrino beam through two functionally identical detectors, a Near detector at the Fermi National Accelerator Laboratory in Illinois, 1km from the beam source, and a Far detector, 734km away, in the Soudan Mine in Minnesota. MINOS may be able to measure the neutrino mixing angle parameter sin{sup 2} 2{theta}{sub 13} for the first time. Detector granularity, however, makes it very hard to distinguish any {nu}{sub e} appearance signal events characteristic of a non-zero value of {theta}{sub 13} from background neutral current (NC) and short-track {nu}{sub {mu}} charged current (CC) events. Also, uncertainties in the hadronic shower modeling in the kinematic region characteristic of this analysis are relatively large. A new data-driven background decomposition method designed to address those issues is developed and its results presented. By removing the long muon tracks from {nu}{sub {mu}}-CC events, the Muon Removed Charge Current (MRCC) method creates independent pseudo-NC samples that can be used to correct the MINOS Monte Carlo to agree with the high-statistics Near detector data and to decompose the latter into components so as to predict the expected Far detector background. The MRCC method also provides an important cross-check in the Far detector to test the background in the signal selected region. MINOS finds a 1.0-1.5 {sigma} {nu}{sub e}-CC excess above background in the Far detector data, depending on method used, for a total exposure of 3.14 x 10{sup 20} protons-on-target. Interpreting this excess as signal, MINOS can set limits on sin{sup 2} 2{theta}{sub 13}. Using the MRCC method, MINOS sets a limit of sin{sup 2} 2{theta}{sub 13} < 0.265 at the 90% confidence limit for a CP-violating phase {delta} = 0