[en] The results and procedure of the alignment of the MINOS Far Detector are presented. The far detector has independent alignments of SM1 and SM2. The misalignments have an estimated uncertainty of ∼850 (micro)m for SM1 and ∼750 (micro)m for SM2. The alignment has as inputs the average rotations of U and V as determined by optical survey and strip positions within modules measured from the module mapper. The output of this is a module-module correction for transverse mis-alignments. These results were verified by examining an independent set of data. These alignment constants on average contribute much less then 1% to the total uncertainty in the transverse strip position

[en] High energy physics facilities must monitor the radiation doses received by their personnel. This monitoring can only be effective if the radiation detection devices can be calibrated with a good degree of accuracy. Radiation fields are usually composed of several types of radiation, including gamma rays, beta radiation, neutrons, etc. The neutron detection instruments respond not only to the neutrons coming directly from the source but also those scattered from the floor, walls, and ceiling. The amount of neutron scattering varies from site to site depending on the construction materials and layout of the building. The purpose of this study was to determine the scattered neutron fraction in the central volume of the calibration mezzanine of the Radiation Physics Calibration Facility (RPCF) at the Fermi National Accelerator Laboratory (Fermilab). At Fermilab, radiation workers dosimeters use CR39 for neutron detection, which are sent to an outside vendor for reading. As part of the quality assurance program, Fermilab routinely sends the vendor ''spiked'' badges, i.e. badges exposed to a known amount of neutron dosage at RPCF. This study determines a correction factor due to scattered neutron to the spiked badges. The study was conducted in a room with floor dimensions of 12 m by 9.5 m. The walls and ceiling are thin steel and insulation supported by steel 1-beams. We determined the total amount of radiation at three heights above the floor, and at three distances from an AmBe neutron source at each height in the RPCF using the Bonner Sphere technique

[en] A Dalitz-plot analysis of 620 E(1420) events was performed on the reaction p-barp→(K/sub S/⁰K⁺π^-)X at 6.6 GeV/c, obtained at the Brookhaven National Laboratory Multiparticle Spectrometer facility. The mass and width of the E(1420) peak are 1424 +- 3 and 60 +- 10 MeV, respectively. The best fit to the E(1420) is a J/sup P//sup G/ -- 0/sup -+/ state with a substantial δπ decay mode, produced over a large nonresonant background of 1/sup ++/ K/sup */K and phase space. This fit shows the same characteristics as the E(1420) observed in our companion π^-p experiment

[en] The authors are studying the reactions bar pp → K⁺ bar K⁰π^- X and bar pp → bar Λpπ X. They present mass spectra for the systems produced in these reactions. The data represent one-half of the total data collected. 3 references, 4 figures

[en] Novel detector schemes are proposed for the short-baseline neutrino experiments of next generation, aimed at exploring the large-Δm² domain of ν_μ→ν_τ oscillations in the appearance mode. These schemes emphasize good spectrometry for charged particles and for electromagnetic showers and efficient reconstruction of π⁰→γγ decays. The basic elements are a sequence of relatively thin emulsion targets, immersed in magnetic field and interspersed with electronic trackers, and a fine-grained electromagnetic calorimeter built of lead glass. These elements act as an integral whole in reconstructing the electromagnetic showers. This conceptual scheme shows good performance in identifying the τ (quasi-) two-body decays by their characteristic kinematics and in selecting the electronic decays of the τ

[en] We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between ν_μ and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of ν_μ oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible contribution to the measured neutral-current event rate at the far site from ν_e appearance at the current experimental limit is also presented

[en] 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 |Δm²|=(2.43±0.13)x10^-3 eV² (68% C.L.) and mixing angle sin²(2θ)>0.90 (90% C.L.). 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

[en] 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, has collected over 67x10⁶ 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, α_T, relating changes in the muon rate to changes in atmospheric temperature was found to be α_T=0.873±0.009(stat)±0.010(syst). Pions and kaons in the primary hadronic interactions of cosmic rays in the atmosphere contribute differently to α_T due to the different masses and lifetimes. This allows the measured value of α_T to be interpreted as a measurement of the K/π ratio for E_p > or approx. 7 TeV of 0.12_-0.05^+0.07, consistent with the expectation from collider experiments.

[en] This paper reports results from a search for ν_μ→ν_e transitions by the MINOS experiment based on a 7x10²⁰ protons-on-target exposure. Our observation of 54 candidate ν_e 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 2sin²(2θ₁₃)sin²θ₂₃<0.12(0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at δ_CP=0. The experiment sets the tightest limits to date on the value of θ₁₃ for nearly all values of δ_CP for the normal neutrino mass hierarchy and maximal sin²(2θ₂₃).

[en] Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07x10²⁰ protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754±28(stat)±37(syst) for oscillations among three active flavors. The fraction f_s of disappearing ν_μ that may transition to ν_s is found to be less than 22% at the 90% C.L.