5,712 research outputs found
Neutrino Telescopes as a Direct Probe of Supersymmetry Breaking
We consider supersymmetric models where the scale of supersymmetry breaking
lies between 5 GeV and 5 GeV. In this class of
theories, which includes models of gauge mediated supersymmetry breaking, the
lightest supersymmetric particle is the gravitino. The next to lightest
supersymmetric particle is typically a long lived charged slepton with a
lifetime between a microsecond and a second, depending on its mass. Collisions
of high energy neutrinos with nucleons in the earth can result in the
production of a pair of these sleptons. Their very high boost means they
typically decay outside the earth. We investigate the production of these
particles by the diffuse flux of high energy neutrinos, and the potential for
their observation in large ice or water Cerenkov detectors. The relatively
small cross-section for the production of supersymmetric particles is partially
compensated for by the very long range of heavy particles. The signal in the
detector consists of two parallel charged tracks emerging from the earth about
100 meters apart, with very little background. A detailed calculation using the
Waxman-Bahcall limit on the neutrino flux and realistic spectra shows that
km experiments could see as many as 4 events a year. We conclude that
neutrino telescopes will complement collider searches in the determination of
the supersymmetry breaking scale, and may even give the first evidence for
supersymmetry at the weak scale.Comment: 4 pages, 3 figure
Melhoramento genético da pimenta-do-reino (Piper nigrum L.).
bitstream/item/57818/1/CPATU-PA179.pd
Diversidade genética entre clones de cupuaçuzeiro com o uso de marcadores moleculares do tipo microssatélites.
Programa Institucional de Bolsas de Iniciação Científica (PIBIC). Disponível também on-line
Characterization of watermelon juice concentrated by reverse osmosis process.
Watermelon is a tropical fruit with excellent flavour, color, sweetness and succulence. Nowadays it is pointed out as an excellent source of lycopene, a carotenoid with antioxidant property. The objective of this work was to concentrate watermelon juice by reverse osmosis to obtain a concentrated product rich in lycopene. The juice was obtained by the depulping the fruits in a finisher with a 0.8 mm. Reverse osmosis was carried out in a pilot plant unit with composite membranes (conditioned in a plate and frame module. totalizing a permeate area of 0.72m2. The process was carried out at 30ºC, 60 bar and 650 L/h flow rate. Samples Lycopene content was determined by extraction with hexane measured in spectrophotometer at 503 nm. Antioxidant capacity s was evaluated by extraction with hexane followed by the quantification using ABTS as radical and Trolox as standard. The color loss was determined in spectrophotometer at 734nm after 15 min of reaction of the sample with the ABTS. The mean permeate flux was 22L1h1m
The DarkSide awakens
The DarkSide program at LNGS aims to perform background-free WIMP searches using two phase liquid argon time projection chambers, with the ultimate goal of covering all parameters down to the socalled neutrino floor. One of the distinct features of the program is the use of underground argon with has a reduced content of the radioactive 39Ar compared to atmospheric argon. The DarkSide Collaboration is currently operating the DarkSide-50 experiment, the first such WIMP detector using underground argo
The DarkSide-50 outer detectors
DarkSide-50 is a dark matter detection experiment searching for Weakly Interacting Massive Particles (WIMPs), in Gran Sasso National Laboratory. For experiments like DarkSide-50, neutrons are one of the primary backgrounds that can mimic WIMP signal
Asympyotic behavior of Musielak-Orlicz-Sobolev modulars
In this article we study the asymptotic behavior of anisotropic nonlocal
nonstandard growth seminorms and modulars as the fractional parameter goes to
1. This gives a so-called Bourgain-Brezis-Mironescu type formula for a very
general family of functionals. In the particu\-lar case of fractional Sobolev
spaces with variable exponent, we point out that our proof asks for a weaker
regularity of the exponent than the considered in previous articles
Podridão do coleto de mudas de mandioca no Estado do Pará causada por Fusarium solani (Mart.) Sacc.
bitstream/item/28093/1/com.tec.67.pd
Finite Size Effects in Thermal Field Theory
We consider a neutral self-interacting massive scalar field defined in a
d-dimensional Euclidean space. Assuming thermal equilibrium, we discuss the
one-loop perturbative renormalization of this theory in the presence of rigid
boundary surfaces (two parallel hyperplanes), which break translational
symmetry. In order to identify the singular parts of the one-loop two-point and
four-point Schwinger functions, we use a combination of dimensional and
zeta-function analytic regularization procedures. The infinities which occur in
both the regularized one-loop two-point and four-point Schwinger functions fall
into two distinct classes: local divergences that could be renormalized with
the introduction of the usual bulk counterterms, and surface divergences that
demand countertems concentrated on the boundaries. We present the detailed form
of the surface divergences and discuss different strategies that one can assume
to solve the problem of the surface divergences. We also briefly mention how to
overcome the difficulties generated by infrared divergences in the case of
Neumann-Neumann boundary conditions.Comment: 31 pages, latex, to appear in J. Math. Phy
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