24,684 research outputs found

    The Super-Kamiokande Experiment

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    Super-Kamiokande is a 50 kiloton water Cherenkov detector located at the Kamioka Observatory of the Institute for Cosmic Ray Research, University of Tokyo. It was designed to study neutrino oscillations and carry out searches for the decay of the nucleon. The Super-Kamiokande experiment began in 1996 and in the ensuing decade of running has produced extremely important results in the fields of atmospheric and solar neutrino oscillations, along with setting stringent limits on the decay of the nucleon and the existence of dark matter and astrophysical sources of neutrinos. Perhaps most crucially, Super-Kamiokande for the first time definitively showed that neutrinos have mass and undergo flavor oscillations. This chapter will summarize the published scientific output of the experiment with a particular emphasis on the atmospheric neutrino results.Comment: Prepared for inclusion in "Neutrino Oscillations: Present Status and Future Plans", J. Thomas and P. Vahle editors, World Scientific Publishing Company, 2008. This version is 12 pages in REVTeX4 two-column forma

    Fleming's bound for the decay of mixed states

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    Fleming's inequality is generalized to the decay function of mixed states. We show that for any symmetric hamiltonian hh and for any density operator ρ\rho on a finite dimensional Hilbert space with the orthogonal projection Π\Pi onto the range of ρ\rho there holds the estimate \Tr(\Pi \rme^{-\rmi ht}\rho \rme^{\rmi ht}) \geq\cos^{2}((\Delta h)_{\rho}t) for all real tt with (Δh)ρtπ/2.(\Delta h)_{\rho}| t| \leq\pi/2. We show that equality either holds for all tRt\in\mathbb{R} or it does not hold for a single tt with 0<(Δh)ρtπ/2.0<(\Delta h)_{\rho}| t| \leq\pi/2. All the density operators saturating the bound for all tR,t\in\mathbb{R}, i.e. the mixed intelligent states, are determined.Comment: 12 page

    Mechanical and Chemical Control of Smooth Cordgrass in Waillapa Bay, Washington

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    We evaluated four methods to control smooth cordgrass (Spartina alterniflora Loisel), hereafter spartina, in Willapa Bay, Washington: mowing, mowing plus herbicide combination, herbicide only for clones, and aerial application of herbicide for meadows. (PDF has 7 pages.

    Self-contained Kondo effect in single molecules

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    Kondo coupling of f and conduction electrons is a common feature of f-electron intermetallics. Similar effects should occur in carbon ring systems(metallocenes). Evidence for Kondo coupling in Ce(C8H8)2 (cerocene) and the ytterbocene Cp*2Yb(bipy) is reported from magnetic susceptibility and L_III-edge x-ray absorption spectroscopy. These well-defined systems provide a new way to study the Kondo effect on the nanoscale, should generate insight into the Anderson Lattice problem, and indicate the importance of this often-ignored contribution to bonding in organometallics.Comment: 4 pages, 5 figures (eps

    Large stellar disks in small elliptical galaxies

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    We present the rotation velocities V and velocity dispersions sigma along the principal axes of seven elliptical galaxies less luminous than M_B= -19.5. These kinematics extend beyond the half-light radii for all systems in this photometrically selected sample. At large radii the kinematics not only confirm that rotation and "diskiness" are important in faint ellipticals, as was previously known, but also demonstrate that in most sample galaxies the stars at large galactocentric distances have (V/sigma)_max of about 2, similar to the disks in bona-fide S0 galaxies. Comparing this high degree of ordered stellar motion in all sample galaxies with numerical simulations of dissipationless mergers argues against mergers with mass ratios <=3:1 as an important mechanism in the final shaping of low-luminosity ellipticals, and favors instead the dissipative formation of a disk.Comment: 11 pages LaTex with 4 Postscript figure

    Study of nuclear recoils in liquid argon with monoenergetic neutrons

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    For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.Comment: 9 pages, 8 figures, proceedings of TAUP 2011, to be published in Journal of Physics: Conference Series (JCPS
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