5,169 research outputs found

    Detecting atmospheric neutrino oscillations in the ATLAS detector at CERN

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    We discuss the possibility to study oscillations of atmospheric neutrinos in the ATLAS experiment at CERN. Due to the large total detector mass, a significant number of events is expected, and during the shutdown phases of the LHC, reconstruction of these events will be possible with very good energy and angular resolutions, and with charge identification. We argue that 500 live days of neutrino running could be achieved, and that a total of ~160 contained \nu_\mu events and ~360 upward going muons could be collected during this time. Despite the low statistics, the excellent detector resolution will allow for an unambiguous confirmation of atmospheric neutrino oscillations and for measurements of the leading oscillation parameters. Though our detailed simulations show that the sensitivity of ATLAS is worse than that of dedicated neutrino experiments, we demonstrate that more sophisticated detectors, e.g. at the ILC, could be highly competitive with upcoming superbeam experiments, and might even give indications for the mass hierarchy and for the value of theta-13.Comment: 8 pages, 4 figures, 2 tables, RevTeX 4; modified treatment of upward going muons, results unchanged; matches published versio

    Gluon Correlators in the Kogan-Kovner Model

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    The Lorentz-invariant gluon correlation functions, corresponding to scalar and pseudo-scalar glueballs, are calculated for Kogan's and Kovner's variational ansatz for the pure SU(N) Yang-Mills wavefunctional. One expects that only one dynamical mass scale should be present in QCD; the ansatz generates the expected scale for both glueballs, as well as an additional scale for the scalar glueball. The additional mass scale must therefore vanish, or be close to the expected one. This is shown to constrain the nature of the phase transition in the Kogan-Kovner ansatz.Comment: 9 pages, no figure

    Implementation of a Gauss convoluted Pandel PDF for track reconstruction in Neutrino Telescopes

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    A probability distribution function is presented which provides a realistic description of the detection of scattered photons. The resulting probabilities can be described analytically by means of a superposition of several special functions. These exact expressions can be evaluated numerically only for small distances and limited time residuals, due to computer accuracy limitations. In this report we provide approximations for the exact expressions in different regions of the distance-time residual space, defined by the detector geometry and the space-time scale of an event. These approximations can be evaluated numerically with a relative error with respect to the exact expression at the boundaries of less than 0.001.Comment: 9 pages, 4 figures Revision 1 : extended content 12 pages, 4 figures Accepted for publication in Astroparticle Physic

    A pseudo-potential analog for zero-range photoassociation and Feshbach resonance

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    A zero-range approach to atom-molecule coupling is developed in analogy to the Fermi-Huang pseudo-potential treatment of atom-atom interactions. It is shown by explicit comparison to an exactly-solvable finite-range model that replacing the molecular bound-state wavefunction with a regularized delta-function can reproduce the exact scattering amplitude in the long-wavelength limit. Using this approach we find an analytical solution to the two-channel Feshbach resonance problem for two atoms in a spherical harmonic trap

    Impedance of a sphere oscillating in an elastic medium with and without slip

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    The dynamic impedance of a sphere oscillating in an elastic medium is considered. Oestreicher's formula for the impedance of a sphere bonded to the surrounding medium can be expressed simply in terms of three lumped impedances associated with the displaced mass and the longitudinal and transverse waves. If the surface of the sphere slips while the normal velocity remains continuous, the impedance formula is modified by adjusting the definition of the transverse impedance to include the interfacial impedance.Comment: 10 pages, 2 figure

    Correlation energy in a spin polarized two dimensional electron liquid in the high density limit

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    We have obtained an analytic expression for the ring diagrams contribution to the correlation energy of a two dimensional electron liquid as a function of the uniform fractional spin polarization. Our results can be used to improve on the interpolation formulas which represent the basic ingredient for the constructions of modern spin-density functionals in two dimensions.Comment: 3 pages, 1 figur

    The role of interactions, tunneling and harmonic confinement on the adiabatic loading of bosons in an optical lattice

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    We calculate entropy-temperature curves for interacting bosons in unit filled optical lattices for both homogeneous and harmonically trapped situations, and use them to understand how adiabatic changes in the lattice depth affect the temperature of the system. In a translationally invariant lattice, the zero tunneling limit facilitates a rather detailed analytic description. Unlike the non-interacting bosonic system which is always cooled upon adiabatic loading for low enough initial temperature, the change in the excitation spectrum induced by interactions can lead to heating. Finite tunneling helps to reduce this heating. Finally, we study the spatially inhomogeneous system confined in a parabolic potential and show that the presence of the trap can significantly reduce the final available temperature, due to the non-vanishing superfluid component at the edge of the cloud which is present in trapped systems.Comment: 9 pages and 6 figures. Two typos in Sec.IIIA were corrected and some references were update

    Nonlinear waves of nuclear density

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    Nonlinear excitations of nuclear density are considered in the framework of semiclassical nonlinear nuclear hydrodynamics. Possible types of stationary nonlinear waves in nuclear media are analysed using Nonlinear Schroedinger equation of fifth order and classified using a simple mechanical picture. It is shown that a rich spectrum of nonlinear oscillations in one-dimensional nuclear medium exist.Comment: 18 pages, 5 figure
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