62,371 research outputs found
750 GeV Diphoton Resonance from Singlets in an Exceptional Supersymmetric Standard Model
The 750-760 GeV diphoton resonance may be identified as one or two scalars
and/or one or two pseudoscalars contained in the two singlet superfields
S_{1,2} arising from the three 27-dimensional representations of E_6 . The
three 27s also contain three copies of colour-triplet charge \mp 1/3
vector-like fermions D,\bar{D} and two copies of charged inert Higgsinos
\tilde{H}^{+},\tilde{H}^{-} to which the singlets S_{1,2} may couple. We
propose a variant of the E_6SSM where the third singlet S_3 breaks a gauged
U(1)_N above the TeV scale, predicting Z'_N, D,\bar{D},
\tilde{H}^{+},\tilde{H}^{-} at LHC Run 2, leaving the two lighter singlets
S_{1,2} with masses around 750 GeV. We calculate the branching ratios and
cross-sections for the two scalar and two pseudoscalar states associated with
the S_{1,2} singlets, including possible degeneracies and maximal mixing,
subject to the constraint that their couplings remain perturbative up to the
unification scale.Comment: 22 pages, 4 figures, some minor changes to the text, references adde
Spectrum of Higgs particles in the Exceptional Supersymmetric Standard Model
We discuss the spectrum of Higgs bosons in the framework of the exceptional
supersymmetric standard model. The presence of a and exotic particles
predicted by the exceptional SUSY model allows the lightest Higgs particle to
be significantly heavier than in the MSSM and NMSSM. When the mass of the
lightest Higgs boson is larger than the heaviest scalar,
pseudoscalar and charged Higgs states lie beyond the range.Comment: Presented at 12th Lomonosov Conference on Elementary Particle
Physics, Moscow, Russia, 25-31 August 2005, some minor changes to the text,
references adde
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
Hidden Stimuli to Capital Formation: Debt and the Incomplete Adjustment of Financial Returns
There is a common belief that the disappointing economic performance in the 1970s can be attributed in good part to the interaction of tax rules, inflation, and capital formation. In this paper, we reassess the relationships between inflation, the tax code, and investment incentives because previous results are based on a number of tenuous assumptions whose impact has not been fully appreciated. We also question the appropriateness of the conventional user cost formulation, and derive an alternative measure taking explicit account of the role of debt -- acquisition,retirement, and net-of-tax interest payments -- and the equity holders' ownership of the firm. Our numerical results show that previously reported disincentives for acquiring capital goods in generaland against longer-lived capital in particular are attenuated, and in a number of cases reversed, under various sets of assumptions. Differences in results stemming from the conventional and modified user costs are highlighted, and are illustrated by a comparison of the U.S. Treasury's tax reform proposals under the two formulations.
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
Black Widow Pulsars: the Price of Promiscuity
The incidence of evaporating 'black widow' pulsars (BWPs) among all
millisecond pulsars (MSPs) is far higher in globular clusters than in the
field. This implies a special formation mechanism for them in clusters. Cluster
MSPs in wide binaries with WD companions exchange them for turnoff-mass stars.
These new companions eventually overflow their Roche lobes because of
encounters and tides. The millisecond pulsars eject the overflowing gas from
the binary, giving mass loss on the binary evolution timescale. The systems are
only observable as BWPs at epochs where this evolution is slow, making the mass
loss transparent and the lifetime long. This explains why observed BWPs have
low-mass companions. We suggest that at least some field BWPs were ejected from
globular clusters or entered the field population when the cluster itself was
disrupted.Comment: 6 pages, 2 figures, MNRAS in pres
Ray methods for free boundary problems
We discuss the use of the WKB ansatz in a variety of parabolic problems involving a small parameter. We analyse the Stefan problem for small latent heat, the Black–Scholes problem for an American put option, and some nonlinear diffusion equations, in each case constructing an asymptotic solution by the use of ray methods
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
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