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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).

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.

The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of \\unit[2070]{mwe} using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the \\unit[5.6]{\\(\\sigma\\)} level and the shadow of the sun at the \\unit[3.8]{\\(\\sigma\\)} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17\\pm 0.12^\\circ. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.

This letter reports results from a search for muon-neutrino to electron-neutrino transitions by the MINOS experiment based on a 7x10^20 protons-on-target exposure. Our observation of 54 candidate electron-neutrino events in the Far Detector with a background of 49.1+/-7.0(stat.)+/-2.7(syst.) events predicted by the measurements in the Near Detector requires 2sin^2(2theta_{13})sin^2(theta_{23})<0.12 (0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at delta_cp=0. The experiment sets the tightest limits to date on the value of theta_{13} for nearly all values of delta_cp for the normal neutrino mass hierarchy and maximal sin^2(2theta_{23}).

The energy dependence of the neutrino-iron and antineutrino-iron inclusive charged-current cross sections and their ratio have been measured using a high-statistics sample with the MINOS Near Detector exposed to the NuMI beam from the Main Injector at Fermilab. Neutrino and antineutrino fluxes were determined using a low hadronic energy subsample of charged-current events. We report measurements of neutrino-Fe (antineutrinoFe) cross section in the energy range 3-50 GeV (5-50 GeV) with precision of 2-8% (3-9%) and their ratio which is measured with precision 2-8%. The data set spans the region from low energy, where accurate measurements are sparse, up to the high-energy scaling region where the cross section is well understood.

A search for depletion of the combined flux of active neutrino species over a 735 km baseline is reported using neutral-current interaction data recorded by the MINOS detectors in the NuMI neutrino beam. Such a depletion is not expected according to conventional interpretations of neutrino oscillation data involving the three known neutrino flavors. A depletion would be a signature of oscillations or decay to postulated non-interacting \"sterile\" neutrinos, scenarios not ruled out by existing data. From an exposure of 3.18x10^{20} protons on target in which neutrinos of energies between ~500 MeV and 120 GeV are produced predominantly as nu_mu, the visible energy spectrum of candidate neutral-current reactions in the MINOS far detector is reconstructed. Comparison of this spectrum to that inferred from a similarly selected near detector sample shows that of the portion of the nu_mu flux observed to disappear in charged-current interaction data, the fraction that could be converting to a sterile state is less than 52% at 90% confidence level (C.L.). The hypothesis that active neutrinos mix with a single sterile neutrino via oscillations is tested by fitting the data to various models. In the particular four-neutrino models considered, the mixing angles theta_{24} and theta_{34} are constrained to be less than 11 degrees and 56 degrees at 90% C.L., respectively. The possibility that active neutrinos may decay to sterile neutrinos is also investigated. Pure neutrino decay without oscillations is ruled out at 5.4 standard deviations. For the scenario in which active neutrinos decay into sterile states concurrently with neutrino oscillations, a lower limit is established for the neutrino decay lifetime tau_3/m_3 > 2.1x10^{-12} s/eV at 90% C.L..

The temperature of the upper atmosphere affects the height of primary cosmic ray interactions and the production of high-energy cosmic ray muons which can be detected deep underground. The MINOS far detector at Soudan MN, USA, has collected over 67 million cosmic ray induced muons. The underground muon rate measured over a period of five years exhibits a 4% peak-to-peak seasonal variation which is highly correlated with the temperature in the upper atmosphere. The coefficient, \\(\\alpha_T\\), relating changes in the muon rate to changes in atmospheric temperature was found to be: \\(\\alpha_T = 0.874 \\pm 0.009\\) (stat.) \\(\\pm 0.010\\) (syst.). Pions and kaons in the primary hadronic interactions of cosmic rays in the atmosphere contribute differently to \\(\\alpha_T\\) due to the different masses and lifetimes. This allows the measured value of \\(\\alpha_T\\) to be interpreted as a measurement of the K/\\(\\pi\\) ratio for \\(E_{p}\\gtrsim\\)\\unit[7]{TeV} of \\(0.13 \\pm 0.08\\), consistent with the expectation from collider experiments.

The MINOS experiment has used the world's most powerful neutrino beam to make precision neutrino oscillation measurements. By observing the disappearance of muon neutrinos, MINOS has made the world's most precise measurement of the larger neutrino mass splitting, and has measured the neutrino mixing angle \\(\\theta_{23}\\). Using a dedicated antineutrino beam, MINOS has made the first direct precision measurements of the corresponding antineutrino parameters. A search for \\nue and \\nuebar appearance has enabled a measurement of the mixing angle \\(\\theta_{13}\\). A measurement of the neutral-current interaction rate has confirmed oscillation between three active neutrino flavours. MINOS will continue as MINOS+ in an upgraded beam with higher energy and intensity, allowing precision tests of the three-flavour neutrino oscillation picture, in particular a very sensitive search for the existence of sterile neutrinos.