179 research outputs found

    Stability estimates for resolvents, eigenvalues and eigenfunctions of elliptic operators on variable domains

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    We consider general second order uniformly elliptic operators subject to homogeneous boundary conditions on open sets ϕ(Ω)\phi (\Omega) parametrized by Lipschitz homeomorphisms ϕ\phi defined on a fixed reference domain Ω\Omega. Given two open sets ϕ(Ω)\phi (\Omega), ϕ~(Ω)\tilde \phi (\Omega) we estimate the variation of resolvents, eigenvalues and eigenfunctions via the Sobolev norm ∥ϕ~−ϕ∥W1,p(Ω)\|\tilde \phi -\phi \|_{W^{1,p}(\Omega)} for finite values of pp, under natural summability conditions on eigenfunctions and their gradients. We prove that such conditions are satisfied for a wide class of operators and open sets, including open sets with Lipschitz continuous boundaries. We apply these estimates to control the variation of the eigenvalues and eigenfunctions via the measure of the symmetric difference of the open sets. We also discuss an application to the stability of solutions to the Poisson problem.Comment: 34 pages. Minor changes in the introduction and the refercenes. Published in: Around the research of Vladimir Maz'ya II, pp23--60, Int. Math. Ser. (N.Y.), vol. 12, Springer, New York 201

    The extended-track reconstruction for MiniBooNE

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    The Booster Neutrino Experiment (MiniBooNE) searches for muon neutrino to electron neutrino oscillations using the ~1 GeV neutrino beam produced by the FNAL Booster synchrotron. The array of photomultiplier tubes (PMTs) lining the MiniBooNE detector records Cherenkov and scintillation photons from the charged particles produced in neutrino interactions. We describe a maximum likelihood fitting algorithm used to reconstruct the basic properties (position, direction, energy) of these particles from the charges and times measured by the PMTs. The likelihoods returned from fitting an event to different particle hypotheses are used to categorize it as a signal electron neutrino event or as one of the background muon neutrino processes, in particular charged current quasi-elastic scattering and neutral current π0\pi^0 production. The reconstruction and event selection techniques described here can be applied to current and future neutrino experiments using similar Cherenkov-based detection.Comment: 39 pages, 25 figures. Version 2 includes minor editorial change

    Search for the decay K+→π+ννˉK^+\to \pi^+ \nu \bar\nu in the momentum region Pπ<195 MeV/cP_\pi < 195 {\rm ~MeV/c}

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    We have searched for the decay K+→π+ννˉK^+ \to \pi^+ \nu \bar\nu in the kinematic region with pion momentum below the K+→π+π0K^+ \to \pi^+ \pi^0 peak. One event was observed, consistent with the background estimate of 0.73±0.180.73\pm 0.18. This implies an upper limit on B(K+→π+ννˉ)<4.2×10−9B(K^+ \to \pi^+ \nu \bar\nu)< 4.2\times 10^{-9} (90% C.L.), consistent with the recently measured branching ratio of (1.57−0.82+1.75)×10−10(1.57^{+1.75}_{-0.82}) \times 10^{-10}, obtained using the standard model spectrum and the kinematic region above the K+→π+π0K^+ \to \pi^+ \pi^0 peak. The same data were used to search for K+→π+X0K^+ \to \pi^+ X^0, where X0X^0 is a weakly interacting neutral particle or system of particles with 150<MX0<250 MeV/c2150 < M_{X^0} < 250 {\rm ~MeV/c^2}.Comment: 4 pages, 2 figure

    First Observation of Coherent π0\pi^0 Production in Neutrino Nucleus Interactions with Eν<E_{\nu}< 2 GeV

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    The MiniBooNE experiment at Fermilab has amassed the largest sample to date of π0\pi^0s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of π0\pi^0s produced in mineral oil (CH2_2) and the first observation of coherent π0\pi^0 production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 ±\pm1.1 (stat) ±\pm2.5 (sys))% of all exclusive NC π0\pi^0 production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for νμ→νe\nu_{\mu} \to \nu_e oscillations.Comment: Submitted to Phys. Lett.

    Further search for the decay K+→π+ννˉK^+ \to \pi^+ \nu \bar \nu in the momentum region P < 195 MeV/c

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    We report the results of a search for the decay K+→π+ννˉK^+ \to \pi^+ \nu \bar \nu in the kinematic region with π+\pi^+ momentum 140<P<195140 < P < 195 MeV/c using the data collected by the E787 experiment at BNL. No events were observed. When combined with our previous search in this region, one candidate event with an expected background of 1.22±0.241.22 \pm 0.24 events results in a 90% C.L. upper limit of 2.2×10−92.2 \times 10^{-9} on the branching ratio of K+→π+ννˉK^+ \to \pi^+ \nu \bar \nu. We also report improved limits on the rates of K+→π+X0K^+ \to \pi^+ X^0 and K+→π+X1X2K^+ \to \pi^+ X^1 X^2 where X0,X1,X2X^0, X^1, X^2 are hypothetical, massless, long-lived neutral particles.Comment: 5 pages, 3 figures, Accepted for publication in Phys. Rev.

    Test of Lorentz and CPT violation with Short Baseline Neutrino Oscillation Excesses

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    The sidereal time dependence of MiniBooNE electron neutrino and anti-electron neutrino appearance data are analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov test shows both the electron neutrino and anti-electron neutrino appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the electron neutrino appearance data prefer a sidereal time-independent solution, and the anti-electron neutrino appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10E-20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for muon neutrino to electron neutrino and anti-muon neutrino to anti-electron neutrino oscillations. The fit values and limits of combinations of SME coefficients are provided.Comment: 14 pages, 3 figures, and 2 tables, submitted to Physics Letters

    Diving into the vertical dimension of elasmobranch movement ecology

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    Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

    Light Yield in DarkSide-10: a Prototype Two-phase Liquid Argon TPC for Dark Matter Searches

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    As part of the DarkSide program of direct dark matter searches using liquid argon TPCs, a prototype detector with an active volume containing 10 kg of liquid argon, DarkSide-10, was built and operated underground in the Gran Sasso National Laboratory in Italy. A critically important parameter for such devices is the scintillation light yield, as photon statistics limits the rejection of electron-recoil backgrounds by pulse shape discrimination. We have measured the light yield of DarkSide-10 using the readily-identifiable full-absorption peaks from gamma ray sources combined with single-photoelectron calibrations using low-occupancy laser pulses. For gamma lines of energies in the range 122-1275 keV, we get consistent light yields averaging 8.887+-0.003(stat)+-0.444(sys) p.e./keVee. With additional purification, the light yield measured at 511 keV increased to 9.142+-0.006(stat) p.e./keVee.Comment: 10 pages, 7 figures, Accepted for publication in Astroparticle Physic

    All-sky search for long-duration gravitational wave transients with initial LIGO

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    We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
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