48 research outputs found

    New Young Star Candidates in BRC 27 and BRC 34

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    We used archival Spitzer Space Telescope mid-infrared data to search for young stellar objects (YSOs) in the immediate vicinity of two bright-rimmed clouds, BRC 27 (part of CMa R1) and BRC 34 (part of the IC 1396 complex). These regions both appear to be actively forming young stars, perhaps triggered by the proximate OB stars. In BRC 27, we find clear infrared excesses around 22 of the 26 YSOs or YSO candidates identified in the literature, and identify 16 new YSO candidates that appear to have IR excesses. In BRC 34, the one literature-identified YSO has an IR excess, and we suggest 13 new YSO candidates in this region, including a new Class I object. Considering the entire ensemble, both BRCs are likely of comparable ages, within the uncertainties of small number statistics and without spectroscopy to confirm or refute the YSO candidates. Similarly, no clear conclusions can yet be drawn about any possible age gradients that may be present across the BRCs.Comment: 54 pages, 19 figures, accepted by A

    Status of the UCNτ experiment

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    The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, τ_n = 877.7s (0.7s)_(stat) (+0.4/−0.2s)_(sys). We discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.25 s measurement of the neutron lifetime with UCNτ

    First Observation of PP-odd γ\gamma Asymmetry in Polarized Neutron Capture on Hydrogen

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    We report the first observation of the parity-violating 2.2 MeV gamma-ray asymmetry AγnpA^{np}_\gamma in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. AγnpA^{np}_\gamma isolates the ΔI=1\Delta I=1, \mbox{3S13P1^{3}S_{1}\rightarrow {^{3}P_{1}}} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless EFT. We measured Aγnp=[3.0±1.4(stat)±0.2(sys)]×108A^{np}_\gamma = [-3.0 \pm 1.4 (stat) \pm 0.2 (sys)]\times 10^{-8}, which implies a DDH weak πNN\pi NN coupling of hπ1=[2.6±1.2(stat)±0.2(sys)]×107h_{\pi}^{1} = [2.6 \pm 1.2(stat) \pm 0.2(sys)] \times 10^{-7} and a pionless EFT constant of C3S13P1/C0=[7.4±3.5(stat)±0.5(sys)]×1011C^{^{3}S_{1}\rightarrow ^{3}P_{1}}/C_{0}=[-7.4 \pm 3.5 (stat) \pm 0.5 (sys)] \times 10^{-11} MeV1^{-1}. We describe the experiment, data analysis, systematic uncertainties, and the implications of the result.Comment: 6 pages, 5 figure

    A Search for Possible Long Range Spin Dependent Interactions of the Neutron from Exotic Vector Boson Exchange

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    We present a search for possible spin dependent interactions of the neutron with matter through exchange of spin 1 bosons with axial vector couplings as envisioned in possible extensions of the Standard Model. This was sought using a slow neutron polarimeter that passed transversely polarized slow neutrons by unpolarized slabs of material arranged so that interactions would tilt the plane of polarization and develop a component along the neutron momentum. The result for the rotation angle, ϕ′=[2.8±4.6(stat.)±4.0(sys.)]×10−5 rad/m is consistent with zero. This result improves the upper bounds on the neutron-matter coupling g2A by about three orders of magnitude for force ranges in the mm– μm regime

    Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

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    Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201
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