1,802 research outputs found

    Quantum Dissipation in a Neutrino System Propagating in Vacuum and in Matter

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    Considering the neutrino state like an open quantum system, we analyze its propagation in vacuum or in matter. After defining what can be called decoherence and relaxation effects, we show that in general the probabilities in vacuum and in constant matter can be written in a similar way, which is not an obvious result in this approach. From this result, we analyze the situation where neutrinos evolution satisfies the adiabatic limit and use this formalim to study solar neutrinos. We show that the decoherence effect may not be bounded by the solar neutrino data and review some results in the literature. We discuss the current results where solar neutrinos were used to put bounds on decoherence effects through a model-dependent approach. We conclude explaining how and why this models are not general and we reinterpret these constraints.Comment: new version: title was changend and was added a table. To appear at Nucl. Physic.

    Neutrino Decay and Solar Neutrino Seasonal Effect

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    We consider the possibility of solar neutrino decay as a sub-leading effect on their propagation between production and detection. Using current oscillation data, we set a new lower bound to the ν2\nu_2 neutrino lifetime at τ2 / m2≥7.2×10−4  s . eV−1\tau_2\, /\, m_2 \geq 7.2 \times 10^{-4}\,\,\hbox{s}\,.\,\hbox{eV}^{-1} at 99% 99\%\,C.L.. Also, we show how seasonal variations in the solar neutrino data can give interesting additional information about neutrino lifetime

    Metodologia de georreferenciamento do Cadastro Vitícola.

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    Big Data in Critical Infrastructures Security Monitoring: Challenges and Opportunities

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    Critical Infrastructures (CIs), such as smart power grids, transport systems, and financial infrastructures, are more and more vulnerable to cyber threats, due to the adoption of commodity computing facilities. Despite the use of several monitoring tools, recent attacks have proven that current defensive mechanisms for CIs are not effective enough against most advanced threats. In this paper we explore the idea of a framework leveraging multiple data sources to improve protection capabilities of CIs. Challenges and opportunities are discussed along three main research directions: i) use of distinct and heterogeneous data sources, ii) monitoring with adaptive granularity, and iii) attack modeling and runtime combination of multiple data analysis techniques.Comment: EDCC-2014, BIG4CIP-201
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