2,667 research outputs found
Supersymmetric Higgs pair discovery prospects at hadron colliders
We study the potential of hadron colliders in the search for the pair
production of neutral Higgs bosons in the framework of the Minimal
Supersymmetric Standard Model. Using analytical expressions for the relevant
amplitudes, we perform a detailed signal and background analysis, working out
efficient kinematical cuts for the extraction of the signal. The important role
of squark loop contributions to the signal is emphasised. If the signal is
sufficiently enhanced by these contributions, it could even be observable at
the next run of the upgraded Tevatron collider in the near future. At the LHC
the pair production of light and heavy Higgs bosons might be detectable
simultaneously.Comment: 5 pages, hep99, 6 figures; Presented at the International Europhysics
Conference on High Energy Physics, Tampere, Finland, 15-21 July 199
DEVELOPING FLEXIBLE ECONOMIC THRESHOLDS FOR PEST MANAGEMENT USING DYNAMIC PROGRAMMING
The rice stink bug is a major pest of rice in Texas, causing quality related damage. The previous threshold used for assisting in rice stink bug spray decisions lacked flexibility in economic and production decision variables and neglected the dynamics of the pest population. Using stochastic dynamic programming, flexible economic thresholds for the rice stink bug were generated. The new thresholds offer several advantages over the old, static thresholds, including increased net returns, incorporation of pest dynamics, user flexibility, ease of implementation, and a systematic process for updating.Economic thresholds, Dynamic programming, Pest management, Rice, Crop Production/Industries,
Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides LaSrCoO
The magnetic excitations in the cuprate superconductors might be essential
for an understanding of high-temperature superconductivity. In these cuprate
superconductors the magnetic excitation spectrum resembles an hour-glass and
certain resonant magnetic excitations within are believed to be connected to
the pairing mechanism which is corroborated by the observation of a universal
linear scaling of superconducting gap and magnetic resonance energy. So far,
charge stripes are widely believed to be involved in the physics of hour-glass
spectra. Here we study an isostructural cobaltate that also exhibits an
hour-glass magnetic spectrum. Instead of the expected charge stripe order we
observe nano phase separation and unravel a microscopically split origin of
hour-glass spectra on the nano scale pointing to a connection between the
magnetic resonance peak and the spin gap originating in islands of the
antiferromagnetic parent insulator. Our findings open new ways to theories of
magnetic excitations and superconductivity in cuprate superconductors.Comment: Nature Communications 5, 5731 (2014
Electronic and magnetic nano phase separation in cobaltates LaSrCoO
The single-layer perovskite cobaltates have attracted enormous attention due
to the recent observation of hour-glass shaped magnetic excitation spectra
which resemble the ones of the famous high-temperature superconducting
cuprates. Here, we present an overview of our most recent studies of the spin
and charge correlations in floating-zone grown cobaltate single crystals. We
find that frustration and a novel kind of electronic and magnetic nano phase
separation are intimately connected to the appearance of the hour-glass shaped
spin excitation spectra. We also point out the difference between nano phase
separation and conventional phase separation.Comment: * plenary talk SUPERSTRIPES conference 201
Cosmic antiprotons as a probe for supersymmetric dark matter?
The flux of cosmic ray antiprotons from neutralino annihilations in the
galactic halo is computed for a large sample of models in the MSSM (the Minimal
Supersymmetric extension of the Standard Model). We also revisit the problem of
estimating the background of low-energy cosmic ray induced secondary
antiprotons, taking into account their subsequent interactions (and energy
loss) and the presence of nuclei in the interstellar matter.
We consider a two-zone diffusion model, with and without a galactic wind. We
find that, given the uncertainties in the background predictions, there is no
need for a primary (exotic) component to explain present data. However,
allowing for a signal by playing with the uncertainties in the background
estimate, we discuss the characteristic features of the supersymmetric models
which give a satisfactory description of the data. We point out that in some
cases the optimal kinetic energy to search for a signal from supersymmetric
dark matter is above several GeV, rather than the traditional sub-GeV region.
The large astrophysical uncertainties involved do not, one the other hand,
allow the exclusion of any of the MSSM models we consider, on the basis of
data.
We present besides numerical results also convenient parameterizations of the
antiproton yields of all `basic' two-body final states. We also give examples
of the yield and differential energy spectrum for a set of supersymmetric
models with high rates.
We also remark that it is difficult to put a limit on the antiproton lifetime
from present measurements, since the injection of antiprotons from neutralino
annihilation can compensate the loss from decay.Comment: 22 pages, 11 figures, uses emulateapj.st
Incommensurate spin correlations in highly oxidized cobaltates LaSrCoO
We observe quasi-static incommensurate magnetic peaks in neutron scattering
experiments on layered cobalt oxides La2-xSrxCoO4 with high Co oxidation states
that have been reported to be paramagnetic. This enables us to measure the
magnetic excitations in this highly hole-doped incommensurate regime and
compare our results with those found in the low-doped incommensurate regime
that exhibit hourglass magnetic spectra. The hourglass shape of magnetic
excitations completely disappears given a high Sr doping. Moreover, broad
low-energy excitations are found, which are not centered at the incommensurate
magnetic peak positions but around the quarter-integer values that are
typically exhibited by excitations in the checkerboard charge ordered phase.
Our findings suggest that the strong inter-site exchange interactions in the
undoped islands are critical for the emergence of hourglass spectra in the
incommensurate magnetic phases of La2-xSrxCoO4.Comment: http://www.nature.com/articles/srep25117
Is there a correlation between infection control performance and other hospital quality measures?
Quality measures are increasingly reported by hospitals to the Centers for Medicare and Medicaid Services (CMS), yet there may be tradeoffs in performance between infection control (IC) and other quality measures. Hospitals that performed best on IC measures did not perform well on most CMS nonâIC quality measures
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