21,891 research outputs found
Search for the Higgs Boson at LHC in 3-3-1 Model
We present an analysis of production and signature of neutral Higgs boson
() on the version of the 3-3-1 model containing heavy leptons at the
Large Hadron Collider. We studied the possibility to identify it using the
respective branching ratios. Cross section are given for the collider energy,
14 TeV. Event rates and significances are discussed for two
possible values of integrated luminosity, 300 fb and 3000 fb.Comment: 17 pages 7 figures. arXiv admin note: substantial text overlap with
arXiv:1205.404
Black hole shadow of a rotating polytropic black hole by the Newman--Janis algorithm without complexification
In this work, starting from a spherically symmetric polytropic black hole, a
rotating solution is obtained by following the Newman--Janis algorithm without
complexification. Besides studying the horizon, the static conditions and
causality issues of the rotating solution, we obtain and discuss the shape of
its shadow. Some other physical features as the Hawking temperature and
emission rate of the rotating polytropic black hole solution are also
discussed.Comment: 9 pages, 2 figures, some references adde
Accounting for Convective Blue-Shifts in the Determination of Absolute Stellar Radial Velocities
For late-type non-active stars, gravitational redshifts and convective
blueshifts are the main source of biases in the determination of radial
velocities. If ignored, these effects can introduce systematic errors of the
order of ~ 0.5 km/s. We demonstrate that three-dimensional hydrodynamical
simulations of solar surface convection can be used to predict the convective
blue-shifts of weak spectral lines in solar-like stars to ~ 0.070 km/s. Using
accurate trigonometric parallaxes and stellar evolution models, the
gravitational redshifts can be constrained with a similar uncertainty, leading
to absolute radial velocities accurate to better than ~ 0.1 km/s.Comment: To appear in the proceedings of the Joint Discussion 10, IAU General
Assembly, Rio de Janeiro, August 10-11, 200
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Damages caused by cotton rat, Sigmodon hispidus zanjonensis, on sugar cane in San Pedrosula, Honduras
Technical assistance was given to Compañía Azucarera Hondureña, S.A. (Agro-Industrial Co.), Honduras, Central America, to determine if a campaign against noxious rodents to agriculture crops was needed. Several trappings were carried out at different places using snap traps to determine the population structure of rodents associated with the crop, and live traps to determine the index or density of the Sigmodon hispidus rat population, which was identified as being responsible for the damage to sugarcane. Results were 43.24% adult males, 14.86% young males, 31.41% adult females, and 10.47% young females. Of the adult females captured, 54.83% were pregnant with an average of 3 to 4 embryos per rat. A control demonstration combat was carried out at one of the experimental stations with a bait prepared with 2% zinc phosphide in a place where it had been previously determined there was a population of 39 rats per hectare. After such control, the population was reduced to 18 rats per hectare, which represents an efficiency of 53.85%. An evaluation of damages was also measured at different places to determine the degree of loss caused by the rats, which proved to be 22.79% damage. The size of the sample was estimated in 3 samples per hectare, with a level of confidence of 95%
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