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We report the final measurement of the neutrino oscillation parameters \\(\\Delta m^2_{32}\\) and \\(\\sin^2\\theta_{23}\\) using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of \\(23.76 \\times 10^{20}\\) protons on target producing \\(\\nu_{mu}\\) and \\(\\overline{\\nu_\\mu}\\) beams and 60.75 kt\\(\\cdot\\)yr exposure to atmospheric neutrinos. The measurement of the disappearance of \\(\\nu_{\\mu}\\) and the appearance of \\(\\nu_e\\) events between the Near and Far detectors yields \\(|\\Delta m^2_{32}|=2.40^{+0.08}_{-0.09}~(2.45^{+0.07}_{-0.08}) \\times 10^{-3}\\) eV\\(^2\\) and \\(\\sin^2\\theta_{23} = 0.43^{+0.20}_{-0.04} ~(0.42^{+0.07}_{-0.03})\\) at 68% C.L. for Normal (Inverted) Hierarchy.

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 \\unit[3.0]{\\(\\sigma\\)} level.

In this paper we present the latest results from the MINOS Experiment. This includes a new measurement of the oscillation parameters (|Δm232|, sin2(2θ23)) based on 3.36 × 1020 protons-on-target of data and a first analysis of neutral current events in the Far Detector. The prospects for νe appearance measurements in MINOS are also discussed.

The MINOS experiment uses two layered scintillator and steel detectors along with a muon neutrino beam to search for νμ disappearance, and thus neutrino oscillations. The Far Detector ( FD ) is situated in a former iron mine in the Soudan Underground Mine State Park in Northeastern MN, 700 m (2070 mwe) below the surface. This 5.4 kt steel/scintillator calorimeter measures the neutrino flux after they have traveled the 735 km baseline. It also detects atmospheric neutrinos at a rate of several per week, and is the first magnetized atmospheric neutrino detector, able to discriminate between νμ and νμ on an event-by-event basis. The similar 1 kt Near Detector ( ND ) is 100 m (220 mwe) underground at Fermilab. This poster discusses the science being done with the high energy cosmic ray muons which penetrate the rock overburden and are seen by the detectors. The typical surface energy of those seen at the FD are ∼1 TeV (coming from ∼8 TeV primary cosmic rays) and ∼110 GeV at the ND (∼900 GeV primaries).

The magnetized MINOS Near Detector, at a depth of 225 meters of water equivalent (mwe), is used to measure the atmospheric muon charge ratio. The ratio of observed positive to negative atmospheric muon rates, using 301 days of data, is measured to be 1.266+/-0.001(stat.)+0.015/-0.014(syst.). This measurement is consistent with previous results from other shallow underground detectors, and is 0.108+/-0.019(stat. + syst.) lower than the measurement at the functionally identical MINOS Far Detector at a depth of 2070 mwe. This increase in charge ratio as a function of depth is consistent with an increase in the fraction of muons arising from kaon decay for increasing muon surface energies.

This letter reports on a search for \\(\\nu_\\mu \\to \\nu_e\\) transitions by the MINOS experiment based on a \\unit[\\(3.14\\times10^{20}\\)]{protons-on-target} exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of \\(27\\pm 5 {\\rm (stat.)} \\pm 2 {\\rm (syst.)\\) events predicted by the measurements in the Near Detector. If interpreted in terms of \\(\\nu_\\mu \\to \\nu_e\\) oscillations, this 1.5 \\(\\sigma\\) excess of events is consistent with \\(\\sin^{2}(2\\theta_{13})\\) comparable to the CHOOZ limit when \\(|\\delmsq{}|\\)=\\unit[2.43\\(\\times 10^{-3}\\)] {\\({\\rm eV^{2}}\\)} and \\sinsq{23}=1.0 are assumed.

This letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum mechanical oscillations of neutrino flavor with mass splitting \\(|\\Delta m^2|=(2.43\\pm 0.13)\\times10^{-3}\\) eV\\(^2\\) (68% confidence level) and mixing angle \\(\\sin^2(2\\theta)>0.90\\) (90% confidence level). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight, namely neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard deviation levels, respectively.

The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.). Using the map of the Soudan rock overburden, the muon momenta as measured underground were projected to the corresponding values at the surface in the energy range 1-7 TeV. Within this range of energies at the surface, the MINOS data are consistent with the charge ratio being energy independent at the two standard deviation level. When the MINOS results are compared with measurements at lower energies, a clear rise in the charge ratio in the energy range 0.3 -- 1.0 TeV is apparent. A qualitative model shows that the rise is consistent with an increasing contribution of kaon decays to the muon charge ratio.

We report an updated measurement of muon neutrino disappearance in the NuMI neutrino beam performed using the MINOS detectors. This preliminary result is based on an increased data set corresponding to 2.50 × 1020 protons on the NuMI target, and incorporates a number of improvements to our analysis. We observe 563 candidate vμ CC interactions in the far detector data, compared with an expectation of 738 ± 30 in the absence of oscillations. A maximum likelihood fit to the observed far detector energy spectrum assuming two-flavour vμ → vτ oscillations yields best fit oscillation parameters of Δm223 = 2.38+0.20−0.16 × 10−3eV2 and sin22θ23 = 1.00−0.08 with errors quoted at the 68% confidence level.

The MINOS experiment has the potential to observe electron neutrino appearance for a set of oscillation parameters that has not been excluded by the CHOOZ experiment. However, the observation of this hypothetical signal relies on an accurate understanding of the backgrounds. In order to understand the backgrounds, an analysis of the MINOS near detector energy spectrum, which contains no oscillated signal, is utilized. The results of this analysis can then be extrapolated to the far detector to yield the background estimate. The details of the signal versus background separation methods and the results of this near detector analysis are discussed.