881 research outputs found
Antineutrino Physics at MINOS
We present two new measurements of antineutrino properties based on a data sample corresponding to 3.2×10^(20) protons-on-target, exploiting MINOS' unique ability to distinguish positive and negative muons and thus separate charged current neutrino and antineutrino interactions event-by-event. The first measurement takes advantage of the 6% antineutrino component of the NuMI neutrino beam to measure antineutrino oscillations between the near and far detectors. We observe 42 events at the far detector with an expectation of 58.3±7.6(stat.)±3.6(syst.) assuming CPT-conserving oscillations, excluding (5.0<Δm(overbar)^2<81)×10^(−3)eV^2 at 90% confidence at maximal mixing. We also present a search for neutrino-antineutrino transitions ν_μ → ν(overbar)_μ, which would result in an excess of antineutrino events in the Far Detector relative to the rate expected from the intrinsic antineutrino component in the neutrino beam. We observe no excess and set a limit of 0.026 on the transition probability at 90% confidence
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Antineutrino Oscillations in the Atmospheric Sector
This 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 {nu}{sub {mu}} {yields} {bar {nu}}{sub {mu}} 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 neutrino-mode and when it is in antineutrino-mode. Antineutrino oscillations are observed at |{Delta}{bar m}{sub atm}{sup 2}| = (3.36{sub -0.40}{sup +0.46}(stat) {+-} 0.06(syst)) x 10{sup -3} eV{sup 2} and sin{sup 2}(2{bar {theta}}{sub 23}) = 0.860{sub -0.12}{sup +0.11}(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
Polyhedral units and network connectivity in calcium aluminosilicate glasses from high-energy x-ray diffraction
Structure factors for Cax/2AlxSi1-xO2 glasses (x=0,0.25,0.5,0.67) extended to
a wave vector of magnitude Q= 40 1/A have been obtained by high-energy x-ray
diffraction. For the first time, it is possible to resolve the contributions of
Si-O, Al-O and Ca-O coordination polyhedra to the experimental atomic pair
distribution functions (PDF). It has been found that both Si and Al are
four-fold coordinated and so participate in a continuous tetrahedral network at
low values of x. The number of network breaking defects in the form of
non-bridging oxygens (NBO's) increases slowly with x until x=0.5 (NBO's ~ 10%
at x=0.5). By x=0.67 the network breaking defects become significant as
evidenced by the significant drop in the average coordination number of Si. By
contrast, Al-O tetrahedra remain free of NBO's and fully integrated in the
Al/Si-O network for all values of x. Calcium maintains a rather uniform
coordination sphere of approximately 5 oxygen atoms for all values of x. The
results suggest that not only Si/Al-O tetrahedra but Ca-O polyhedra, too, play
a role in determining the glassy structure
The synthesis and properties of the phases obtained by solid-solid reactions
The presented work encompasses the subject of the studies and the results obtained over the last years by the research workers of the Department of Inorganic Chemistry. They include mainly the studies on the reactivity of metal oxides, searching for new phases in binary and ternary systems of metal oxides as well as describing phase relations establishing in such systems. They also encompass works on the extensive characteristics of physico-chemical properties of the newly obtained compounds
4-(Benzyloxy)benzaldehyde
The title compound, C14H12O2, has an essentially planar conformation with the two aromatic rings forming a dihedral angle of 5.23 (9)° and the aldehyde group lying in the plane of its aromatic group [maximum deviation = 0.204 (3) Å]. Weak intermolecular C—H⋯O contacts are found to be shortest between the aldehyde O-atom acceptor and the H atoms of the methylene group
[Ni(cod)<sub>2</sub>][Al(OR<sup>F</sup>)<sub>4</sub>], a source for naked nickel(I) chemistry
Discrepancies between prescribed and defined daily doses: a matter of patients or drug classes?
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