19,162 research outputs found

    Constraints on neutrino decay lifetime using long-baseline charged and neutral current data

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    We investigate the status of a scenario involving oscillations and decay for charged and neutral current data from the MINOS and T2K experiments. We first present an analysis of charged current neutrino and anti-neutrino data from MINOS in the framework of oscillation with decay and obtain a best fit for non-zero decay parameter α3\alpha_3. The MINOS charged and neutral current data analysis results in the best fit for ∣Δm322∣=2.34×10−3|\Delta m_{32}^2| = 2.34\times 10^{-3}~eV2^2, sin⁥2Ξ23=0.60\sin^2 \theta_{23} = 0.60 and zero decay parameter, which corresponds to the limit for standard oscillations. Our combined MINOS and T2K analysis reports a constraint at the 90\% confidence level for the neutrino decay lifetime τ3/m3>2.8×10−12\tau_3/m_3 > 2.8 \times 10^{-12}~s/eV. This is the best limit based only on accelerator produced neutrinos

    Quantum decoherence and relaxation in neutrinos using long-baseline data

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    We investigate the effect of quantum decoherence and relaxation in neutrino oscillations using MINOS and T2K data. The formalism of open quantum systems is used to describe the interaction of a neutrino system with the environment, where the strength of the interaction is regulated by a decoherence parameter Γ\Gamma. We assume an energy dependence parameterized by \Gamma = \gamma_0 (E/\mbox{GeV})^n, with n=−2,0,+2n=-2,0,+2, and study three different scenarios. The MINOS and T2K data present a complementary behavior, with regard to our theoretical model, resulting in a better sensitivity for n=+2n = +2 and n=−2n = -2, respectively. We perform a combined analysis of both experimental data and include a reactor constraint on sin⁡2ξ13\sin^2 \theta_{13}. The results of our combined analyses improve significantly the previous bounds on γ0\gamma_0 for n=−2n = -2, reporting an upper bound of 1.7×10−231.7 \times 10^{-23}~GeV, at the 90\% confidence level.Comment: Corrected typo

    Plastic Deformation of 2D Crumpled Wires

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    When a single long piece of elastic wire is injected trough channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper it is investigated this packing process but using plastic wires which give origin to completely irreversible structures of different morphology. In particular, it is studied experimentally the plastic deformation from circular to oblate configurations of crumpled wires, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility, and very large deformations, scaling is still observed.Comment: 5 pages, 6 figure

    Magnetocaloric effect in manganites: metamagnetic transitions for magnetic refrigeration

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    We present a study of the magnetocaloric effect in La5/8-yPryCa3/8MnO3 (y=0.3) and Pr0.5Ca0.09Sr0.41MnO3 manganites. The low temperature state of both ystems is the result of a competition between the antiferromagnetic and ferromagnetic phases. The samples display magnetocaloric effect evidenced in an adiabatic temperature change during a metamagnetic transition from an antiferromagnetic to a ferromagnetic phase . As additional features, La5/8-yPryCa3/8MnO3 exhibits phase separation characterized by the coexistence of antiferromagnetic and ferromagnetic phases and Pr0.5Ca0.09Sr0.41MnO3 displays inverse magnetocaloric effect in which temperature decreases while applying an external magnetic field. In both cases, a significant part of the magnetocaloric effect appears from non-reversible processes. As the traditional thermodynamic description of the effect usually deals with reversible transitions, we developed an alternative way to calculate the adiabatic temperature change in terms of the change of the relative ferromagnetic fraction induced by magnetic field. To evaluate our model, we performed direct measurement of the sample's adiabatic temperature change by means of a differential thermal analysis. An excellent agreement has been obtained between experimental and calculated data. These results show that metamagnetic transition in manganites play an important role in the study of magnetic refrigeration.Comment: Acepted to be published in Applied Physics Letter

    Diretrizes para transferĂȘncia de tecnologia: modelo de incubação de empresas.

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    Diretrizes para transferĂȘncia de tecnologia; TransferĂȘncia de tecnologia; Incubação de empresas; Planos de negĂłcio e planejamento de marketing.bitstream/item/117504/1/snt-doc-02a.pd

    Visible neutrino decay in the light of appearance and disappearance long-baseline experiments

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    FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESWe investigate the present constraints from MINOS and T2K experiments for the neutrino decay scenario induced by non-diagonal couplings of Majorons to neutrinos. As novelty, on top of the typical invisible decay prescription, we add the contribution of visible decay, where final products can be observed. This new effect depends on the nature of the neutrino-Majoron coupling, which can be of scalar or pseudoscalar type. Using the combination of disappearance data from MINOS and disappearance and appearance data from T2K, for normal ordering, we constrain the decay para alpha E Gamma for the heaviest neutrino, where E and are the neutrino energy and width, respectively. We find that when considering visible decay within appearance data, alpha < O (10(-5))eV(2), at 90% C.L., for both kinds of couplings, which is better by one order of magnitude compared to previous bounds.11129FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES014/19164-62015/20129-3311980/2013-9461147/2014-9Sem informaçãoA.M.G. and J.J.P. acknowledge funding by the Direccion de Gestion de la Investigacion at PUCP, through grant DGI-2015-3-0026. They would also like to thank S. Sanchez for discussions on the use of GENIE, as well as O.A. Diaz in the Direccion de Tecnologias de Informacion at PUCP, for implementing our code within the LEGION system. A.M.G is thankful for the Unicamp hospitality and for the support of the FAPESP funding grant 2015/20129-3. A.M.G and O.L.G.P are also thankful to the Oficina de Internacionalizacion de la Investigacion at PUCP. A.L.G. G. is supported by CAPES, and R.A.G. would like to thanks CNPq grants 461147/2014-9 and 311980/2013-9. O.L.G.P. is thankful for the PUCP hospitality and partial support under the Programa Latino Americano de Fisica (PLAF) from Brazilian Physics Society. He is also thankful for the support of FAPESP funding grant 2014/19164-6 and CNPq research fellowship 307269/2013-2 and 304715/2016-6 and partial funding from ICTP

    The complex Sine-Gordon equation as a symmetry flow of the AKNS Hierarchy

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    It is shown how the complex sine-Gordon equation arises as a symmetry flow of the AKNS hierarchy. The AKNS hierarchy is extended by the ``negative'' symmetry flows forming the Borel loop algebra. The complex sine-Gordon and the vector Nonlinear Schrodinger equations appear as lowest negative and second positive flows within the extended hierarchy. This is fully analogous to the well-known connection between the sine-Gordon and mKdV equations within the extended mKdV hierarchy. A general formalism for a Toda-like symmetry occupying the ``negative'' sector of sl(N) constrained KP hierarchy and giving rise to the negative Borel sl(N) loop algebra is indicated.Comment: 8 pages, LaTeX, typos corrected, references update

    Integrable Field Theories with Defects

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    The structure of integrable field theories in the presence of defects is discussed in terms of boundary functions under the Lagrangian formalism. Explicit examples of bosonic and fermionic theories are considered. In particular, the boundary functions for the super sinh-Gordon model is constructed and shown to generate the Backlund transformations for its soliton solutions.Comment: talk presented at the XVth International Colloquium on Integrable Systems and Quantum Symmetries, to appear in Czechoslovak Journal of Physics (2006
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