18 research outputs found

    First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector

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    The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nuµ and [overline nu ]µ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nuµ and [overline nu ]µ interactions are separated. The ratio of [overline nu ]µ to nuµ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nuµ and [overline nu ]µ

    Observation of Muon Neutrino Disappearance with the MINOS Detectors in the NuMI Neutrino Beam

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    This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current νμ interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27×1020 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336±14 events. The data are consistent with νμ disappearance via oscillations with |Δm322|=2.74-0.26+0.44×10-3  eV2 and sin⁡2(2θ23)>0.87 (68% C.L.)

    Characterization of molecular and cellular phenotypes associated with a heterozygous deletion using patient-derived hiPSC neural cells

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    Neurodevelopmental disorders, such as autism spectrum disorders (ASD) and schizophrenia (SZ), are complex disorders with a high degree of heritability. Genetic studies have identified several candidate genes associated with these disorders, including contactin-associated protein-like 2 (CNTNAP2). Traditionally, in animal models or in vitro, the function of CNTNAP2 has been studied by genetic deletion or transcriptional knockdown, which reduce the expression of the entire gene; however, it remains unclear whether the mutations identified in clinical settings are sufficient to alter CNTNAP2 expression in human neurons. Here, using human induced pluripotent stem cells (hiPSCs) derived from two individuals with a large (289kb) and heterozygous deletion in CNTNAP2 (affecting exons 14-15) and discordant clinical outcomes, we have characterized CNTNAP2 expression patterns in hiPSC neural progenitor cells (NPCs), two independent populations of hiPSC-derived neurons and hiPSC-derived oligodendrocyte precursor cells (OPCs). First, we observed exon-specific changes in CNTNAP2 expression in both carriers; although the expression of exons 14-15 is significantly decreased, the expression of other exons is upregulated. Second, we observed significant differences in patterns of allele-specific expression in CNTNAP2 carriers that were consistent with clinical outcome. Third, we observed a robust neural migration phenotype that correlated with diagnosis and exon- and allele-specific CNTNAP2 expression patterns, but not with genotype. In all, our data highlight the importance of considering the nature, location and regulation of mutated alleles when attempting to connect GWAS studies to gene function

    Feasibility study 2 of a muon based neutrino source

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    Recent progress in neutrino factory and muon collider research within the Muon collaboration

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    We describe the status of our effort to realize a first neutrino factory and the progress made in understanding the problems associated with the collection and cooling of muons towards that end. We summarize the physics that can be done with neutrino factories as well as with intense cold beams of muons. The physics potential of muon colliders is reviewed, both as Higgs Factories and compact high energy lepton colliders. The status and timescale of our research and development effort is reviewed as well as the latest designs in cooling channels including the promise of ring coolers in achieving longitudinal and transverse cooling simultaneously. We detail the efforts being made to mount an international cooling experiment to demonstrate the ionization cooling of muons
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