70,929 research outputs found
A Next-to-Minimal Supersymmetric Model of Hybrid Inflation
We propose a model of inflation based on a simple variant of the NMSSM,
called NMSSM, where the additional singlet plays the role of the
inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM,
the NMSSM solves the problem of the MSSM via the VEV of a gauge
singlet , but unlike the NMSSM does not suffer from domain wall problems
since the offending 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 symmetry after
compactification. The model predicts a spectral index to one part in
.Comment: 17 pages, Latex; note added, accepted for Phys. Lett.
Head impact exposure in junior and adult Australian football players
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
We consider an extension of the Standard Model involving two new scalar
particles around the TeV scale: a singlet neutral scalar , to be
eventually identified as the Dark Matter candidate, plus a doubly charged
singlet scalar, , that can be the source for the
non-vanishing neutrino masses and mixings. Assuming an unbroken symmetry
in the scalar sector, under which only the additional neutral scalar 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
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
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
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
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
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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