20,509 research outputs found

    The tension between gauge coupling unification, the Higgs boson mass, and a gauge-breaking origin of the supersymmetric mu-term

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    We investigate the possibility of generating the μ\mu-term in the MSSM by the condensation of a field that is a singlet under the SM gauge group but charged under an additional family-independent U(1)XU(1)_X gauge symmetry. We attempt to do so while preserving the gauge coupling unification of the MSSM. For this, we find that SM non-singlet exotics must be present in the spectrum. We also prove that the pure U(1)XU(1)_X anomalies can always be solved with rationally charged fields, but that a large number of SM singlets are often required. For U(1)XU(1)_X charges that are consistent with an embedding of the MSSM in SU(5) or SO(10), we show that the U(1)XU(1)_X charges of the MSSM states can always be expressed as a linear combination of abelian subgroups of E6E_6. However, the SM exotics do not appear to have a straightforward embedding into GUT multiplets. We conclude from this study that if this approach to the μ\mu-term is correct, as experiment can probe, it will necessarily complicate the standard picture of supersymmetric grand unification.Comment: 10 pages, no figure

    How Can a Heavy Higgs Boson be Consistent with the Precision Electroweak Measurements?

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    The fit of precision electroweak data to the Minimal Standard Model currently gives an upper limit on the Higgs boson mass of 170 GeV at 95% confidence. Nevertheless, it is often said that the Higgs boson could be much heavier in more general models. In this paper, we critically review models that have been proposed in the literature that allow a heavy Higgs boson consistent with the precision electroweak constraints. All have unusual features, and all can be distinguished from the Minimal Standard Model either by improved precision measurements or by other signatures accessible to next-generation colliders.Comment: 25 pages, 5 eps figures. Source contains html and jar files which make Fig. 1 active. v.3: final corrections and added reference

    Investigation of upper-surface-blowing nacelle integration at cruise speeds utilizing powered engine simulators

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    Various overwing nacelle designs were investigated on a representative four engine short haul aircraft configuration during a combined analytical and experimental program. Design conditions were M sub o = 0.7 and C sub L = 0.4. All nacelles had D shaped nozzle exits and included a streamline contoured design, a low boattail angle reference configuration, and a high boattail angle powered lift design. Testing was done with the design four engine airplane configuration as well as with only inboard nacelles installed. Turbopowered engine simulators were used to provide realistic representation of nacelle flows. Performance trends are compared for the various nacelle designs. In addition, comparisons are presented between analytical and experimental pressure distributions and between flow through and powered simulator results

    Understanding the role of promoters in catalysis: operando XAFS/DRIFTS study of CeO<sub>x</sub>/Pt/Al<sub>2</sub>O<sub>3</sub> during CO oxidation

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    A combined operando XAFS/DRIFTS study on CeOx/Pt/Al2O3 catalysts has been performed during CO oxidation and provides insights into the changes in nanoparticle structure and adsorbed species during the reaction profile. The onset of CO2 formation is shown to be concurrent with a rapid re-oxidation of the Pt nanoparticles, evidenced by XAFS spectroscopy, and the loss of bridge bonded CO adsorbed on Pt, as shown by simultaneous DRIFTS acquisition. The continued appearance of linear bound CO on the catalyst surface is shown to remain long after catalytic light off. The interaction of Pt and CeOx is evidenced by the improved performance towards CO oxidation, compared to the non-CeOx modified Pt/Al2O3, and changes in the CO adsorption properties on Pt previously linked to Pt-CeO2 interfaces

    Holomorphic selection rules, the origin of the mu term, and thermal inflation

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    When an abelian gauge theory with integer charges is spontaneously broken by the expectation value of a charge Q field, there remains a Z_Q discrete symmetry. In a supersymmetric theory, holomorphy adds additional constraints on the operators that can appear in the effective superpotential. As a result, operators with the same mass dimension but opposite sign charges can have very different coupling strengths. In the present work we characterize the operator hierarchies in the effective theory due to holomorphy, and show that there exist simple relationships between the size of an operator and its mass dimension and charge. Using such holomorphy-induced operator hierarchies, we construct a simple model with a naturally small supersymmetric mu term. This model also provides a concrete realization of late-time thermal inflation, which has the ability to solve the gravitino and moduli problems of weak-scale supersymmetry.Comment: 18 pages, 1 figur

    Cosmic Archaeology with Gravitational Waves from Cosmic Strings

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    Cosmic strings are generic cosmological predictions of many extensions of the Standard Model of particle physics, such as a U(1)′U(1)^\prime symmetry breaking phase transition in the early universe or remnants of superstring theory. Unlike other topological defects, cosmic strings can reach a scaling regime that maintains a small fixed fraction of the total energy density of the universe from a very early epoch until today. If present, they will oscillate and generate gravitational waves with a frequency spectrum that imprints the dominant sources of total cosmic energy density throughout the history of the universe. We demonstrate that current and future gravitational wave detectors, such as LIGO and LISA, could be capable of measuring the frequency spectrum of gravitational waves from cosmic strings and discerning the energy composition of the universe at times well before primordial nucleosynthesis and the cosmic microwave background where standard cosmology has yet to be tested. This work establishes a benchmark case that gravitational waves may provide an unprecedented, powerful tool for probing the evolutionary history of the very early universe.Comment: 6 pages, 3 figure

    Resource management implications of ERTS-1 data to Ohio

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    Initial experimental analysis of ERTS-1 imagery has demonstrated that remote sensing from space is a means of delineating and inventorying Ohio's strip-mined areas, detecting power plant smoke plumes, and proving the data necessary for periodically compiling land use maps for the entire state. The nature and extent of these problems throughout Ohio, how ERTS data can contribute to their solution, and estimates of the long term significance of these initial findings to overall resource management interests in Ohio are summarized

    Solar radiation observation stations with complete listing of data archived by the National Climatic Center, Asheville, North Carolina and initial listing of data not currently archived

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    A listing is provided of organizations taking solar radiation data, the 166 stations where observations are made, the type of equipment used, the form of the recorded data, and the period of operation of each station. Included is a listing of the data from 150 solar radiation stations collected over the past 25 years and stored by the National Climatic Center
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