50 research outputs found

    Cold Dark Matter detection in SUSY models at large tan(beta)

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    We study the direct detection rate for SUSY cold dark matter (CDM) predicted by the minimal supersymmetric standard model with universal boundary conditions and large values for tan(beta). The relic abundance of the lightest supersymmetric particle (LSP), assumed to be approximately a bino, is obtained by including its coannihilations with the next-to-lightest supersymmetric particle (NLSP), which is the lightest s-tau. The cosmological constraint on this quantity severely limits the allowed SUSY parameter space, especially in the case the CP-even Higgs has mass of around 114 GeV. We find that for large tan(beta) it is possible to find a subsection of the allowed parameter space, which yields detectable rates in the currently planned experiments.Comment: Changes in text and figure

    Photon mixing in universes with large extra-dimensions

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    In presence of a magnetic field, photons can mix with any particle having a two-photon vertex. In theories with large compact extra-dimensions, there exists a hierachy of massive Kaluza-Klein gravitons that couple to any photon entering a magnetic field. We study this mixing and show that, in comparison with the four dimensional situation where the photon couples only to the massless graviton, the oscillation effect may be enhanced due to the existence of a large number of Kaluza-Klein modes. We give the conditions for such an enhancement and then investigate the cosmological and astrophysical consequences of this phenomenon; we also discuss some laboratory experiments. Axions also couple to photons in the same way; we discuss the effect of the existence of bulk axions in universes with large extra-dimensions. The results can also be applied to neutrino physics with extra-dimensions.Comment: 41 pages, LaTex, 6 figure

    Introduction and Historical Review

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