9,093 research outputs found
Probing the messenger of supersymmetry breaking by the muon anomalous magnetic moment
Motivated by the recently measured muon's anomalous magnetic moment
, we examine the supersymmetry contribution to in various
mediation models of supersymmetry breaking which lead to predictive flavor
conserving soft parameters at high energy scale. The studied models include
dilaton/modulus-mediated models in heterotic string/ theory, gauge-mediated
model, no-scale or gaugino-mediated model, and also the minimal and deflected
anomaly-mediated models. For each model, the range of allowed
by other experimental constraints, e.g. b --> s\gamma and the collider bounds
on superparticle masses, is obtained together with the corresponding parameter
region of the model. Gauge-mediated models with low messenger scale can give
any within the bound. In many other models, b -->
s\gamma favors smaller than either the value
() or the central value ().Comment: RevTeX, 29 pages, 14 eps figures, figure for deflected anomaly
mediation is corrected, reference adde
Non-thermal WIMP baryogenesis
We propose a WIMP baryogensis achieved by the annihilation of non-thermally
produced WIMPs from decay of heavy particles, which can result in low reheating
temerature. Dark matter (DM) can be produced non-thermally during a reheating
period created by the decay of long-lived heavy particle, and subsequently
re-annihilate to lighter particles even after the thermal freeze-out. The
re-annihilation of DM provides the observed baryon asymmetry as well as the
correct relic density of DM. We investigate how wahout effects can affect the
generation of the baryon asymmetry and study a model suppressing them. In this
scenario, we find that DM can be heavy enough and its annihilation cross
section can also be larger than that adopted in the usual thermal WIMP
baryogenesis.Comment: 5 pages, 6 figure
A Study on Thermal Modeling and Heat Load Mitigation for Satellite Electronic Components
Since most of the satellite components are using various EEE (Electrical, Electronic and Electromechanical) parts, the reliability of EEE parts acts very important in the satellite system. There are many factors that influence the reliability of EEE parts in the satellite system. Excessively dissipated heat can cause the failure of EEE parts and consequently, leading to a failure of total satellite system. In this paper, the thermal modeling using nodal network was compared with that using plate modeling to find out which one is the most suitable methodology. For a comparison, KOMPSAT- 1 SAR was modeled by two different modeling and the result was discussed. There was almost no difference in the numerical results between the two modeling methods. However, while it took much more time to perform thermal analysis using the nodal network modeling method, and the debugging was more difficult in the plate modeling method when the error is occurred. The computation time was considerably reduced by developing and implementing the input file format transfer code when using nodal network modeling method. It was found that the nodal network modeling method is suitable for the complicated components, such as SAR or transponder, because of its simple debugging ability. Excessive heat load was expected on some EEE parts of SAR such as high heat-dissipated diodes, transistors, and inductors due to increased power requirements of KOMPSAT-2 satellite system. The methods for the mitigation of heat load were studied through the design change of housing or the layout change of high power parts
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