12,783 research outputs found

    Exploring Complex Phases of the MSSM at Future Colliders

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    Once Supersymmetry is discovered, exploring the phases of supersymmetric parameters will be one of the most important tasks of future colliders. We analyze the possibilities of investigating the phases of the cMSSM via their effects on the Higgs sector through radiative corrections. Within two benchmark scenarios we compare the capabilities of the LHC, the ILC and a future gamma gamma collider.Comment: 6 pages, 10 figures. Talk given by S. Heinemeyer at the 2005 International Linear Collider Workshop, Stanford Ca (LCWS05

    The connection between entropy and the absorption spectra of Schwarzschild black holes for light and massless scalar fields

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    We present heuristic arguments suggesting that if EM waves with wavelengths somewhat larger than the Schwarzschild radius of a black hole were fully absorbed by it, the second law of thermodynamics would be violated, under the Bekenstein interpretation of the area of a black hole as a measure of its entropy. Thus, entropy considerations make the well known fact that large wavelengths are only marginally absorbed by black holes, a natural consequence of thermodynamics. We also study numerically the ingoing radial propagation of a scalar field wave in a Schwarzschild metric, relaxing the standard assumption which leads to the eikonal equation, that the wave has zero spatial extent. We find that if these waves have wavelengths larger that the Schwarzschild radius, they are very substantially reflected, fully to numerical accuracy. Interestingly, this critical wavelength approximately coincides with the one derived from entropy considerations of the EM field, and is consistent with well known limit results of scattering in the Schwarzschild metric. The propagation speed is also calculated and seen to differ from the value cc, for wavelengths larger than RsR_{s}, in the vicinity of RsR_{s}. As in all classical wave phenomena, whenever the wavelength is larger or comparable to the physical size of elements in the system, in this case changes in the metric, the zero extent 'particle' description fails, and the wave nature becomes apparent.Comment: 14 Pages, 4 figures. Accepted for publication in the Journal Entrop

    Effects of an extra ZZ' gauge boson on the top quark decay t>cγt --> c \gamma

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    The effects of an extra ZZ' gauge boson with family nonuniversal fermion couplings on the rare top quark decay t>ct --> c gammaarefirstexaminedinamodelindependentwayandthenintheminimal331model.Itisfoundthattherespectivebranchingfractionisatmostoftheorderof are first examined in a model independent way and then in the minimal 331 model. It is found that the respective branching fraction is at most of the order of 10^{-8}for for m_{Z'}=500GeVanddramaticallydecreasesforaheavier GeV and dramatically decreases for a heavier Z'boson.Thisresultsisinsharpcontrastwithapreviousevaluationofthisdecayinthecontextoftopcolorassistedtechnicolormodels,whichfoundthat boson. This results is in sharp contrast with a previous evaluation of this decay in the context of topcolor assisted technicolor models, which found that B(t --> c \gamma)\sim 10^{-6}for for m_{Z'}=1$ TeV.Comment: New paragraphs included to clarify our results, conclusion remains unchange