332 research outputs found
Synthesis of N,N-bispropargylanilines via Eglinton coupling-the potential acyclic molecular tweezers
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First Measurement of Electron Neutrino Appearance in NOvA
We report results from the first search for nu(mu) -\u3e nu(e) transitions by the NOvA experiment. In an exposure equivalent to 2.74 x 10(20) protons on target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of 0.99 +/- 0.11 (syst) events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of 1.07 +/- 0.14 (syst). The 3.3 sigma excess of events observed in the primary analysis disfavors 0.1 pi \u3c delta(CP) \u3c 0.5 pi in the inverted mass hierarchy at the 90% C.L
Electron Neutrino and Antineutrino Appearance in the Full MINOS Data Sample
We report on v(e) and (v) over bar (e) appearance in v(mu) and (v) over bar (mu) beams using the full MINOS data sample. The comparison of these v(e) and (v) over bar (e) appearance data at a 735 km baseline with theta(13) measurements by reactor experiments probes delta, the theta(23) octant degeneracy, and the mass hierarchy. This analysis is the first use of this technique and includes the first accelerator long-baseline search for (v) over bar (mu) -\u3e (v) over bar (e). Our data disfavor 31% (5%) of the three-parameter space defined by delta, the octant of the theta(23), and the mass hierarchy at the 68% (90%) C.L. We measure a value of 2sin(2)(2 theta(13))sin(2)(theta(23)) that is consistent with reactor experiments. DOI: 10.1103/PhysRevLett.110.17180
Precision measurement of the speed of propagation of neutrinos using the MINOS detectors
We report a two-detector measurement of the propagation speed of neutrinos over a baseline of 734 km. The measurement was made with the NuMI beam at Fermilab between the near and far MINOS detectors. The fractional difference between the neutrino speed and the speed of light is determined to be (v/c - 1) = (1.0 +/- 1.1) x 10(-6), consistent with relativistic neutrinos
Observation of seasonal variation of atmospheric multiple-muon events in the MINOS Near and Far Detectors
We report the first observation of seasonal modulations in the rates of cosmic ray multiple-muon events at two underground sites, the MINOS Near Detector with an overburden of 225 mwe, and the MINOS Far Detector site at 2100 mwe. At the deeper site, multiple-muon events with muons separated by more than 8 m exhibit a seasonal rate that peaks during the summer, similar to that of single-muon events. In contrast and unexpectedly, the rate of multiple-muon events with muons separated by less than 5-8 m, and the rate of multiple-muon events in the smaller, shallower Near Detector, exhibit a seasonal rate modulation that peaks in the winter
Measurement of the multiple-muon charge ratio in the MINOS Far Detector
The charge ratio, R-mu = N mu + / N mu-, for cosmogenic multiple-muon events observed at an underground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be R mu = 1.104 + / - 0.006(stat)(-0.010)( + 0.009) (syst). This measurement complements previous determinations of single-muon and multiple-muon charge ratios at underground sites and serves to constrain models of cosmic-ray interactions at TeV energies
Combined Analysis of nu(mu) Disappearance and nu(mu) -\u3e nu(e) Appearance in MINOS Using Accelerator and Atmospheric Neutrinos
We report on a new analysis of neutrino oscillations in MINOS using the complete set of accelerator and atmospheric data. The analysis combines the nu(mu) disappearance and nu(e) appearance data using the three-flavor formalism. We measure vertical bar Delta m(32)(2)vertical bar = [2.28-2.46] x 10(-3) eV(2) (68% C.L.) and sin(2)theta(23) = 0.35-0.65 (90% C.L.) in the normal hierarchy, and vertical bar Delta m(32)(2)vertical bar = [2.32-2.53] x 10(-3) eV(2) (68% C.L.) and sin(2)theta(23) = 0.34-0.67 (90% C.L.) in the inverted hierarchy. The data also constrain delta(CP), the theta(23) octant degeneracy and the mass hierarchy; we disfavor 36% (11%) of this three-parameter space at 68% (90%) C.L
Comparisons of annual modulations in MINOS with the event rate modulation in CoGeNT
The CoGeNT Collaboration has recently published results from a fifteen month data set which indicate an annual modulation in the event rate similar to what is expected from weakly interacting massive particle interactions. It has been suggested that the CoGeNT modulation may actually be caused by other annually modulating phenomena, specifically the flux of atmospheric muons underground or the radon level in the laboratory. We have compared the phase of the CoGeNT data modulation to that of the concurrent atmospheric muon and radon data collected by the MINOS experiment which occupies an adjacent experimental hall in the Soudan Underground Laboratory. The results presented are obtained by performing a shape-free chi(2) data-to-data comparison and from a simultaneous fit of the MINOS and CoGeNT data to phase-shifted sinusoidal functions. Both tests indicate that the phase of the CoGeNT modulation is inconsistent with the phases of the MINOS muon and radon modulations at the 3.0 sigma level. DOI: 10.1103/PhysRevD.87.03200
Identification of Nuclear Effects in Neutrino-Carbon Interactions at Low Three-Momentum Transfer
Two different nuclear-medium effects are isolated using a low three-momentum transfer subsample of neutrino-carbon scattering data from the MINERvA neutrino experiment. The observed hadronic energy in charged-current nu(mu) interactions is combined with muon kinematics to permit separation of the quasielastic and Delta(1232) resonance processes. First, we observe a small cross section at very low energy transfer that matches the expected screening effect of long-range nucleon correlations. Second, additions to the event rate in the kinematic region between the quasielastic and Delta resonance processes are needed to describe the data. The data in this kinematic region also have an enhanced population of multiproton final states. Contributions predicted for scattering from a nucleon pair have both properties; the model tested in this analysis is a significant improvement but does not fully describe the data. We present the results as a double-differential cross section to enable further investigation of nuclear models. Improved description of the effects of the nuclear environment are required by current and future neutrino oscillation experiments
Observation of muon intensity variations by season with the MINOS near detector
A sample of 1.53 x 10(9) cosmic-ray-induced single muon events has been recorded at 225 m water equivalent using the MINOS near detector. The underground muon rate is observed to be highly correlated with the effective atmospheric temperature. The coefficient alpha(T), relating the change in the muon rate to the change in the vertical effective temperature, is determined to be 0.428 +/- 0.003(stat.) +/- 0.059(syst.). An alternative description is provided by the weighted effective temperature, introduced to account for the differences in the temperature profile and muon flux as a function of zenith angle. Using the latter estimation of temperature, the coefficient is determined to be 0.352 +/- 0.003(stat.) +/- 0.046(syst.)
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