1,295 research outputs found

    The Maximal Neutrino Flux from Neutralino Annihilation in the Galactic Center

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    We discuss a robust and fairly model-independent upper bound on the possible neutrino flux produced by neutralino annihilation in the center of our galaxy, and show that its detection with present or future neutrino telescopes is highly improbable. This bound is obtained by relating the neutrino flux to the gamma flux that would be produced in the same annihilation processes, for which measurements do exist.Comment: 4 pages, 4 figures, uses floatfl

    Leptogenesis: a Link between the Matter-Antimatter Asymmetry and Neutrino Physics

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    We review the experimental evidence for a net baryon density in cosmology, and the theoretical mechanism for producing it, called leptogenesis, which relies on the creation of a lepton asymmetry at an intermediate step. The naturality of this mechanism and its possible relations with neutrino oscillations are outlined.Comment: 11 pages, 6 figures; presented at the XXXVIII Rencontres de Moriond: Electroweak Interactions and Unified Theories, Les Arcs, France, 15-22 March 200

    Supersymmetric penguin contributions to the decay b -> s gamma with non-universal squarks masses

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    We give explicit expressions for the amplitudes associated with the supersymmetric contributions to the process: b -> s gamma in the context of SUSY extensions of Standard Model with non-universal soft SUSY breaking terms. From experimental data, we deduce the limits on the squark mass insertions obtained from different contributions (gluinos, neutralinos and charginos).Comment: 13 pages, 6 figures, changes: added remarks and new referenc

    Neutrino Indirect Detection of Neutralino Dark Matter in the CMSSM

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    We study potential signals of neutralino dark matter indirect detection by neutrino telescopes in a wide range of CMSSM parameters. We also compare with direct detection potential signals taking into account in both cases present and future experiment sensitivities. Only models with neutralino annihilation into gauge bosons can satisfy cosmological constraints and current neutrino indirect detection sensitivities. For both direct and indirect detection, only next generation experiments will be able to really test this kind of models.Comment: 16 pages, 19 figures; v4: a few clarifications and significant improvement of reference

    Indirect Detection of CMSSM Neutralino Dark Matter with Neutrino Telescopes

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    We review the prospects of detecting supersymmetric dark matter in the framework of the Constrained Minimal Supersymmetric Standard Model, and compare indirect with direct detection capabilities.Comment: 6 pages, 4 figures, presented by J. Orloff at the York IDM02 workshop (http://www.shef.ac.uk/~phys/idm2002

    Higgs self coupling measurement in e+e- collisions at center-of-mass energy of 500 GeV

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    Feasibility of the measurement of the trilinear self-couplings of the Higgs boson is studied. Such a measurement would experimentally determine the structure of the Higgs potential. Full hadronic and semi-leptonic final states of the double-Higgs strahlung have been investigated.Comment: 10 pages, 5 tables, 8 figure

    A Comparison of Lanthanum Hexaboride, Cold FIeld Emission and Thermal Field Emission Electron Guns for Low Voltage Scanning Electron Microscopy

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    A comparison of lanthanum hexaboride, cold W(310) field emission and Zr/W thermal field emission cathodes was made by calculating the current-spot size relationship for each, using comparable lenses, to determine which would be suitable for high current operation at 1 keV beam energy, with a focused beam diameter \u3c 0.05 ÎĽm. On the criteria of highest current, reasonable operating conditions for the gun for low noise operation and long term cathode stability it was found that the lanthanum hexaboride and cold field emission cathodes are inadequate or marginal and that the best performance is obtainable from the thermal field emission cathode

    Standard Model Baryogenesis

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    Simply on CP arguments, we argue against a Standard Model explanation of baryogenesis via the charge transport mechanism. A CP-asymmetry is found in the reflection coefficients of quarks hitting the electroweak phase boundary created during a first order phase transition. The problem is analyzed both in an academic zero temperature case and in the realistic finite temperature one. At finite temperature, a crucial role is played by the damping rate of quasi-quarks in a hot plasma, which induces loss of spatial coherence and suppresses reflection on the boundary even at tree-level. The resulting baryon asymmetry is many orders of magnitude below what observation requires. We comment as well on related works.Comment: 10 pages, CERN-TH. 7368/94, LPTHE Orsay-94/71, HD-THEP-94-2

    Budd-Chiari Syndrome: Shunt or Transplant?

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