45,499 research outputs found

    Engineering knowledge requirements for sand and dust on Mars

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    The successful landing of human beings on Mars and the establishment of a permanent outpost there will require an understanding of the Martian environment by the engineers. A key feature of the Martian environment is the nearly ubiquitous presence of sand and dust. The process which the engineering community will undertake to determine the sensitivities of their designs to the current level of knowledge about Mars sand and dust is emphasized. The interaction of the engineering community with the space exploration initiative (SEI) mission planners and management is described

    Gaugino-Assisted Anomaly Mediation

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    We present a model of supersymmetry breaking mediated through a small extra dimension. Standard model matter multiplets and a supersymmetry-breaking (or ``hidden'') sector are confined to opposite four-dimensional boundaries while gauge multiplets live in the bulk. The hidden sector does not contain a singlet and the dominant contribution to gaugino masses is via anomaly-mediated supersymmetry breaking. Scalar masses get contributions from both anomaly mediation and a tiny hard breaking of supersymmetry by operators on the hidden-sector boundary. These operators contribute to scalar masses at one loop and in most of parameter space, their contribution dominates. Thus it is easy to make all squared scalar masses positive. As no additional fields or symmetries are required below the Planck scale, we consider this the simplest working model of anomaly mediation. The gaugino spectrum is left untouched and the phenomenology of the model is roughly similar to anomaly mediated supersymmetry breaking with a universal scalar mass added. We identify the main differences in the spectrum between this model and other approaches. We also discuss mechanisms for generating the mu term and constraints on additional bulk fields.Comment: LaTeX, 26 pages, 8 eps figure

    Physics of An Ultrahigh-Statistics Charm Experiment

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    We review the physics goals of an ultrahigh-statistics charm experiment and place them in the broader context of the community's efforts to study the Standard Model and to search for physics beyond the Standard Model, and we point out some of the experimental difficulties which must be overcome if these goals are to be met.Comment: 9 pages, no figure

    Status of MICE

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    Muon ionization cooling is the only practical method for preparing high-brilliance beams needed for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) under development at the Rutherford Appleton Laboratory comprises a dedicated beamline to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating-fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen with RF acceleration. A second spectrometer identical to the first and a particle identification system will measure the outgoing emittance. Plans for measurements of emittance and cooling are described.Comment: Poster presented at ICHEP08 Conference, Philadelphia, USA, July 2008. 3 pages, 3 figure
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