24,880 research outputs found
Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam
No full textThis Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27x10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 +/- 14 events. The data are consistent with nu(mu) disappearance via oscillations with vertical bar Delta m(32)(2)vertical bar=2.74(-0.26)(+0.44)x10(-3) eV(2) and sin(2)(2 theta(23))> 0.87 (68% C.L.)
Antineutrino Oscillations in the Atmospheric Sector
No full textThis thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for νμ \to ν̅ μ transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in FHC and when it is in RHC. Antineutrino oscillations are observed at |Δm̅2atm| = (3.36+0.46-0.40(stat)±0.06(syst)) x 10- eV2 and sin2(2θ̅23 = 0.860+0.11-0.12(stat)± 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions
Search for flavor-changing nonstandard neutrino interactions using nu(e) appearance in MINOS
No full textWe report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS long-baseline experiment using nu(e) and (nu) over bar (e) appearance candidate events from predominantly nu(mu) and (nu) over bar (mu) beams. We used a statistical selection algorithm to separate nu(e) candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, vertical bar epsilon(e tau)vertical bar, and phase, (delta(CP) + delta(e tau)), using a 30-bin likelihood fit.Physic
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The MINOS Scintillator Calorimeter System
No full textThe MINOS detectors will use extruded plastic scintillator strips, which are read out by wavelength-shifting fibers coupled to multipixel photodetectors. This technique provides excellent energy and spatial resolution. The MINOS detectors are described in detail along with results from light output tests
Precision constraints for three-flavor neutrino oscillations from the full MINOS+ and MINOS dataset
No full textWe report the final measurement of the neutrino oscillation parameters Δm_{32}^{2} and sin^{2}θ_{23} using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of 23.76×10^{20} protons on target producing ν_{μ} and ν[over ¯]_{μ} beams and 60.75 kt yr exposure to atmospheric neutrinos. The measurement of the disappearance of ν_{μ} and the appearance of ν_{e} events between the Near and Far detectors yields |Δm_{32}^{2}|=2.40_{-0.09}^{+0.08}(2.45_{-0.08}^{+0.07})×10^{-3} eV^{2} and sin^{2}θ_{23}=0.43_{-0.04}^{+0.20}(0.42_{-0.03}^{+0.07}) at 68% C.L. for normal (inverted) hierarchy
Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam
No full textThis letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 \pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |\Delta m^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3} eV^2/c^4 and sin^2(2\theta_{23}) > 0.87 (at 60% C.L.)
The Structure of Scientific Collaboration Networks in Scientometrics
No full textThe structure of scientific collaboration networks in scientometrics was investigated at the level of individuals by using bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation Index (SCI) during 1978 to 2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis and frequency analysis of words was explored to reveal: (1) The microstructure of the collaboration network on scientists’ aspects of scientometrics; (2) The major collaborative fields of the collaborative sub-networks; (3) The collaborative center of the collaboration network in scientometrics
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The Fermilab long-baseline neutrino program
No full textFermilab is embarking upon a neutrino oscillation program which includes a long-baseline neutrino experiment MINOS. MINOS will be a 10 kiloton detector located 730 km Northwest of Fermilab in the Soudan underground laboratory. It will be sensitive to neutrino oscillations with parameters above {Delta}m{sup 2} {approximately} 3 {times} 10{sup {minus}3} eV{sup 2} and sin{sup 2}(2{theta}) {approximately} 0.02
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Search for flavor-changing nonstandard neutrino interactions using ?e appearance in MINOS
No full textWe report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS longbaseline experiment using ?e and ¯?e appearance candidate events from predominantly ?µ and ¯?µ beams. We used a statistical selection algorithm to separate ?e candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, |eet|, and phase, (dCP + det), using a 30-bin likelihood fit
Search for flavor-changing nonstandard neutrino interactions using ?e appearance in MINOS
No full textWe report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS longbaseline experiment using ?e and ¯?e appearance candidate events from predominantly ?µ and ¯?µ beams. We used a statistical selection algorithm to separate ?e candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, |eet|, and phase, (dCP + det), using a 30-bin likelihood fit
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