421 research outputs found
Heavy MSSM Higgs production at the LHC and decays to WW,ZZ at higher orders
In this paper we discuss the production of a heavy scalar MSSM Higgs boson H
and its subsequent decays into pairs of electroweak gauge bosons WW and ZZ. We
perform a scan over the relevant MSSM parameters, using constraints from direct
Higgs searches and several low-energy observables. We then compare the possible
size of the pp -> H -> WW,ZZ cross sections with corresponding Standard Model
cross sections. We also include the full MSSM vertex corrections to the H ->
WW,ZZ decay and combine them with the Higgs propagator corrections, paying
special attention to the IR-divergent contributions. We find that the vertex
corrections can be as large as -30% in MSSM parameter space regions which are
currently probed by Higgs searches at the LHC. Once the sensitivity of these
searches reaches two percent of the SM signal strength the vertex corrections
can be numerically as important as the leading order and Higgs self-energy
corrections and have to be considered when setting limits on MSSM parameters
The Higgs sector of the complex minimal supersymmetric standard model
Complete one-loop results for the decay widths of neutral Higgs bosons ( h(_a)) into lighter neutral Higgs bosons ( h(_b), h(_c). ) arc presented for the MSSM with complex parameters. The results are obtained in the Feynman-diagrammatic approach, taking into account the full dependence on the spectrum of supersymmetric particles and all complex phases of the supersymmetric parameters. The genuine triple-Higgs vertex contributions are supplemented with two-loop propagator-type corrections, yielding the currently most precise prediction for this class of processes. The genuine vertex corrections turn out to be very important, yielding a large increase of the decay width compared to a prediction based on the tree-level vertex. One-loop propagator-type mixing between neutral Higgs bosons and Goldstone and Z bosons is also consistently taken into account. Complete one-loop results for the decay of a neutral Higgs boson into fermions are also presented, which include the full dependence on complex phases. The new results are used to analyse the impact of the experimental limits from the LEP Higgs searches on the parameter space with a very light MSSM Higgs boson. It is found that a significant part of the parameter space of the CPX benchmark scenario exists where channels involving the decay h(_2)→ h(_1) h(_1) have the highest search sensitivity, and the existence of an unexcluded region with M(_h1) ~ 45 GeV is confirmed. The public code Higgs Bounds is also presented, which can be used in conjunction with models with an arbitrary number of neutral Higgs bosons to determine whether parameter points have been excluded at the 95% CL by the LEP and Tevatron Higgs searches
FORAGING ECOLOGY OF PSITTACINES IN THE TAMBOPATA NATIONAL RESERVE
Between May 2004 and April 2005 we observed 15 species of psittacines foraging along transects and during fortuitous encounters in the Tambopata National Reserve. Psittacines fed on 84 plant species from 62 genera and 30 families. We report 51 plant species as new food sources for psittacines in Southeastern Peru. The greatest foraging activity took place from 6:00 h to 7:00 h. The most consumed plant part was the seed (41% of 469 foraging encounters), followed by pulp (15%), whole fruit (13%), flower (12%), aril (10%), leaves (1.5%), bark (0.6%), floral buds (0.4%) and fruit juice (0.4%). We found no preference between ripe and unripe seed consumption (48% and 47% respectively), but other fruit parts were eaten mostly ripe (more than 67%)
Evaluation of JULES-crop performance against site observations of irrigated maize from Mead, Nebraska
We use the results to point to future priorities for model development and describe how our methodology can be adapted to set up model runs for other sites and crop varietie
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