946 resultados para neutrino experiments
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We show in this Letter that the observation of the angular distribution of upward-going muons and cascade events induced by atmospheric neutrinos at the TeV energy scale which can be performed by a kilometer-scale neutrino telescope, such as the IceCube detector, can be used to probe a large neutrino mass splitting, |Δm 2| ∼ (0.5-2.0) eV 2, implied by the LSND experiment and discriminate among four neutrino mass schemes. This is due to the fact that such a large mass scale can promote non-negligible v μ → v e, v τ/v μ → v e, v τ conversions at these energies by the MSW effect as well as vacuum oscillation, unlike what is expected if all the neutrino mass splittings are small. © 2003 Elsevier Science B.V. All rights reserved.
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We analyse the production of multileptons in the simplest supergravity model with bilinear violation of R parity at the Fermilab Tevatron. Despite the small .R-parity violating couplings needed to generate the neutrino masses indicated by current atmospheric neutrino data, the lightest supersymmetric particle is unstable and can decay inside the detector. This leads to a phenomenology quite distinct from that of the R-parity conserving scenario. We quantify by how much the supersymmetric multilepton signals differ from the R-parity conserving expectations, displaying our results in the m0 ⊙ m1/2 plane. We show that the presence of bilinear R-parity violating interactions enhances the supersymmetric multilepton signals over most of the parameter space, specially at moderate and large m0. © SISSA/ISAS 2003.
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The objective of this article is to apply the Design of experiments technique along with the Discrete Events Simulation technique in an automotive process. The benefits of the design of experiments in simulation include the possibility to improve the performance in the simulation process, avoiding trial and error to seek solutions. The methodology of the conjoint use of Design of Experiments and Computer Simulation is presented to assess the effects of the variables and its interactions involved in the process. In this paper, the efficacy of the use of process mapping and design of experiments on the phases of conception and analysis are confirmed. © 2007 IEEE.
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We report a search for R-parity-violating production and decay of sneutrino particles in the eμ final state with 1.04±0.06fb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2006. Good agreement between the data and the standard model prediction is observed. With no evidence for new physics, we set limits on the R-parity-violating couplings λ311′ and λ312 as a function of the sneutrino mass. © 2008 The American Physical Society.
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The tourism policies pursued by the Brazilian government since the 1990s have not produced the benefits that were expected from mass tourism. The example of two very successful cases of community-based tourism, stressing paths rooted in a development model that is fair and environmentally responsible, shows that tourism development can improve the quality of life in communities that receive an influx of tourists provided that the local community is taken into account and the planning and implementation of such development focus on creating opportunities and benefits for its members. © 2008 Latin American Perpectives.
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The objective of this article is to apply the Design of Experiments technique along with the Discrete Events Simulation technique in an automotive process. The benefits of the design of experiments in simulation include the possibility to improve the performance in the simulation process, avoiding trial and error to seek solutions. The methodology of the conjoint use of Design of Experiments and Computer Simulation is presented to assess the effects of the variables and its interactions involved in the process. In this paper, the efficacy of the use of process mapping and design of experiments on the phases of conception and analysis are confirmed.
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A body of knowledge in Software Engineering requires experiments replications. The knowledge generated by a study is registered in the so-called lab package, which, must be reviewed by an eventual research group with the intention to replicate it. However, researchers face difficulties reviewing the lab package, what leads to problems in share knowledge among research groups. Besides that, the lack of standardization is an obstacle to the integration of the knowledge from an isolated study in a common body of knowledge. In this sense, ontologies can be applied, since they can be seen as a standard that promotes the shared understanding of the experiment information structure. In this paper, we present a workflow to generate lab packages based on EXPEiiQntology, an ontology of controlled experiments domain. In addition, by means of lab packages instantiation, it is possible to evolve the ontology, in order to deal with new concepts that may appear in different lab packages. The iterative ontology evolution aims at achieve a standard that is able to accommodate different lab packages and, hence, facilitate to review and understand their content.
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A recently proposed scenario for baryogenesis, called post-sphaleron baryogenesis (PSB), is discussed within a class of quark-lepton unified framework based on the gauge symmetry SU(2)L×SU(2) R×SU(4)c realized in the multi-TeV scale. The baryon asymmetry of the Universe in this model is produced below the electroweak phase transition temperature after the sphalerons have decoupled from the Hubble expansion. These models embed naturally the seesaw mechanism for neutrino masses and predict color-sextet scalar particles in the TeV range which may be accessible to the LHC experiments. A necessary consequence of this scenario is the baryon-number-violating ΔB=2 process of neutron-antineutron (n-n̄) oscillations. In this paper we show that the constraints of PSB, when combined with the neutrino oscillation data and restrictions from flavor changing neutral currents mediated by the colored scalars, imply an upper limit on the n-n̄ oscillation time of 5×1010 sec regardless of the quark-lepton unification scale. If this scale is relatively low, in the (200-250) TeV range, τn-n̄ is predicted to be less than 1010 sec, which is accessible to the next generation of proposed experiments. © 2013 American Physical Society.
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We present a general model of brain function (the calcium wave model), distinguishing three processing modes in the perception-action cycle. The model provides an interpretation of the data from experiments on semantic memory conducted by the authors. © 2013 Pereira Jr, Santos and Barros.
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Phylogenetic approaches based on mitochondrial DNA variation (fragments of Cyt B and 16S ribosomal RNA) have revealed Triatoma sherlocki as the most recent species addition to the Triatoma brasiliensis species complex; a monophyletic group which includes T. brasiliensis, Triatoma melanica, and Triatoma juazeirensis. T. sherlocki is the most differentiated among all species of this complex: it is unable to fly, possesses longer legs than the other members, and has reddish tonality in some parts of its exochorion. We question whether these species are reproductively compatible because of this pronounced morphological differentiation, and therefore, we present a series of cross breeding experiments that test compatibility between T. sherlocki and other members of the T. brasiliensis complex. We extended our analyses to include crosses between T. sherlocki and Triatoma lenti, because the latter has been suggested as a possible member of this complex. T. sherlocki male. ×. T. lenti female pairs failed to produce hybrids. All other crosses of T. sherlocki and members of T. brasiliensis species complex, as well as backcrosses, produced viable offspring through the third generation. This study stresses the importance of searching for the features that may isolate members of the T. brasiliensis species complex. © 2013 Elsevier B.V.
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Includes bibliography
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We point out that the usual experimental upper bounds on the ''tau-neutrino mass'' do not apply if neutrino mixing is considered. The suppression of the population of the tau decay spectrum near the end point, caused by mixing, may be compensated by an enhancement because of a resonant mechanism of hadronization. It is necessary therefore to analyze the whole spectrum to infer some limit to the '' tau-neutrino mass.'' We argue that, consequently, neutrino mixing evades the objection to interpret the KARMEN anomaly as a heavy sequential neutrino.