69,093 research outputs found

    A Next-to-Minimal Supersymmetric Model of Hybrid Inflation

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    We propose a model of inflation based on a simple variant of the NMSSM, called Ď•\phiNMSSM, where the additional singlet Ď•\phi plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the Ď•\phiNMSSM solves the ÎĽ\mu problem of the MSSM via the VEV of a gauge singlet NN, but unlike the NMSSM does not suffer from domain wall problems since the offending Z3Z_3 symmetry is replaced by an approximate Peccei-Quinn symmetry which also solves the strong CP problem, and leads to an invisible axion with interesting cosmological consequences. The PQ symmetry may arise from a superstring model with an exact discrete Z3Ă—Z5Z_3 \times Z_5 symmetry after compactification. The model predicts a spectral index n=1n=1 to one part in 101210^{12}.Comment: 17 pages, Latex; note added, accepted for Phys. Lett.

    Head impact exposure in junior and adult Australian football players

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    Tis study measured and compared the frequency, magnitude, and distribution of head impacts sustained by junior and adult Australian football players, respectively, and between player positions over a season of games. Twelve junior and twelve adult players were tracked using a skin-mounted impact sensor. Head impact exposure, including frequency, magnitude, and location of impacts, was quantifed using previously established methods. Over the collection period, there were no signifcant diferences in the impact frequency between junior and adult players. However, there was a signifcant increase in the frequency of head impacts for midfelders in both grades once we accounted for player position. A comparable amount of head impacts in both junior and adult players has implications for Australian football regarding player safety and medical coverage as younger players sustained similar impact levels as adult players. Te other implication of a higher impact profle within midfelders is that, by targeting education and prevention strategies, a decrease in the incidence of sports-related concussion may result

    Higgs portal dark matter and neutrino mass and mixing with a doubly charged scalar

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    We consider an extension of the Standard Model involving two new scalar particles around the TeV scale: a singlet neutral scalar Ď•\phi, to be eventually identified as the Dark Matter candidate, plus a doubly charged SU(2)LSU(2)_L singlet scalar, S++S^{++}, that can be the source for the non-vanishing neutrino masses and mixings. Assuming an unbroken Z2Z_2 symmetry in the scalar sector, under which only the additional neutral scalar Ď•\phi is odd, we write the most general (renormalizable) scalar potential. The model may be regarded as a possible extension of the conventional Higgs portal Dark Matter scenario which also accounts for neutrino mass and mixing. This framework cannot completely explain the observed positron excess. However a softening of the discrepancy observed in conventional Higgs portal framework can be obtained, especially when the scale of new physics responsible for generating neutrino masses and lepton number violating processes is around 2 TeV.Comment: 16 pages, 4 figure

    LHC Signatures of the Constrained Exceptional Supersymmetric Standard Model

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    We discuss two striking Large Hadron Collider (LHC) signatures of the constrained version of the exceptional supersymmetric standard model (cE6SSM), based on a universal high energy soft scalar mass m_0, soft trilinear coupling A_0 and soft gaugino mass M_{1/2}. The first signature we discuss is that of light exotic colour triplet charge 1/3 fermions, which we refer to as D-fermions. We calculate the LHC production cross section of D-fermions, and discuss their decay patterns. Secondly we discuss the E6 type U(1)_N spin-1 Z' gauge boson and show how it may decay into exotic states, increasing its width and modifying the line shape of the dilepton final state. We illustrate these features using two representative cE6SSM benchmark points, including an "early LHC discovery" point, giving the Feynman rules and numerical values for the relevant couplings in order to facilitate further studies.Comment: 30 pages, 5 figures, corrections to figure caption

    Geology of the Mohon Mountain volcanic field, Yavapai and Mohave Counties, Arizona: A preliminary report

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    Field mapping has produced a preliminary picture of Mohon Mountain as a composite volcano, in which pyroclastic ash and larger tephra erupted alternately with flows of rhyodacite and dacite. An analog study which uses imagery of lunar and Martian features will compare the overall shape of the vent complex, including its breached southern flank and satellite vents, to similar landforms found on Mars and the Moon which are believed to have formed similar processes. Ash flow sheets were hypothesized to comprise the outer slopes of Olympus Mons suggesting that explosive eruptions which are more volatile-rich than those which produce basalt flows are not confined to terrestrial settings but may also be found on bodies such as Mars, which have a thicker crust and deeper magma source in the mantle. The analog study will explore further evidence for explosive eruptions on Mars and the Moon

    Community-based participatory irrigation management at local government level in Ghana

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    Ghana has attempted to decentralise the management of irrigation schemes to communities at local government level. This study examines the existing local participatory management structures and the principles of the Participatory Irrigation Management (PIM) strategy designed to promote sustainable management of irrigation schemes in Ghana. Two community-based irrigation projects, Bontanga and Golinga in the Northern Region of Ghana were selected for the research. The study demonstrated that farmers’ participation was minimal and limited to the discussion of irrigation service charges at the expense of other issues related to the sustainability of the projects/schemes. The study also established that there was less participation of women, and more than half of all the crop farmers on the two irrigation projects were reluctant to assume additional responsibilities without remuneration. The study therefore concluded that the sustainability of the PIM strategy depends on the adoption of an integrated management approach involving all stakeholders including local government, with appropriate incentives

    Discovery Prospects for NMSSM Higgs Bosons at the High-Energy Large Hadron Collider

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    We investigate the discovery prospects for NMSSM Higgs bosons during the 13~TeV run of the LHC. While one of the neutral Higgs bosons is demanded to have a mass around 125~GeV and Standard Model (SM)-like properties, there can be substantially lighter, nearby or heavier Higgs bosons, that have not been excluded yet by LEP, Tevatron or the 8~TeV run of the LHC. The challenge consists in discovering the whole NMSSM Higgs mass spectrum. We present the rates for production and subsequent decay of the neutral NMSSM Higgs bosons in the most promising final states and discuss their possible discovery. The prospects for pinning down the Higgs sector of the Natural NMSSM will be analysed taking into account alternative search channels. We give a series of benchmark scenarios compatible with the experimental constraints, that feature Higgs-to-Higgs decays and entail (exotic) signatures with multi-fermion and/or multi-photon final states. These decay chains furthermore give access to the trilinear Higgs self-couplings. We briefly discuss the possibility of exploiting coupling sum rules in case not all the NMSSM Higgs bosons are discovered

    Model for the unidirectional motion of a dynein molecule

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    Cytoplasmic dyneins transport cellular organelles by moving on a microtubule filament. It has been found recently that depending on the applied force and the concentration of the adenosine triphosphate (ATP) molecules, dynein's step size varies. Based on these studies, we propose a simple model for dynein's unidirectional motion taking into account the variations in its step size. We study how the average velocity and the relative dispersion in the displacement vary with the applied load. The model is amenable to further extensions by inclusion of details associated with the structure and the processivity of the molecule.Comment: 10 pages, 5 figure
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