322 research outputs found

    Possible scenario for MaVaN's as the only neutrino flavor conversion mechanism in the Sun

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    Mass Varying neutrino mechanisms were proposed to link the neutrino mass scale with dark energy, addressing the coincidence problem. In some scenarios this mass can present a dependence on the baryonic density felt by neutrinos, creating an effective neutrino mass that depends both on the neutrino and baryonic densities. In this article we investigate the possibility that a neutrino effective mass is the only flavour conversion mechanism acting in neutrino oscillation experiments. We present a parameterization on the environmental effects on neutrino mass that produces the right flavour conversion probabilities for solar and terrestrial neutrinos experiments.Comment: 12 pages, 4 figure

    MonetDBLite: An embedded analytical database

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    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.

    Relational queries with a tensor processing unit

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    Tensor Processing Units are specialized hardware devices built to train and apply Machine Learning models at high speed through high-bandwidth memory and massive instruction parallelism. In this short paper, we investigate how relational operations can be translated to those devices. We present mapping of relational operators to TPU-supported TensorFlow operations and experimental results comparing with GPU and CPU implementations. Results show that while raw speeds are enticing, TPUs are unlikely to improve relational query processing for now due to a variety of issues

    REPRESENTAÇÕES SOBRE A MORTE EM FORTALEZA-CE (1920 – 1940)

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    Com a constatação da relevância dos estudos históricos acerca dos temas vinculados à morte, o presente trabalho, cujo objetivo é investigar as práticas e representações fúnebres na cidade de Fortaleza – CE, parte da percepção de que as mudanças ocorridas na cidade e no seu cotidiano entre os anos de 1920 e 1940 acarretam novas formas de convivência e ritualização dos atos fúnebres e suas representações. Para esse estudo, utilizou-se as obras de dois memorialistas que escreveram sobre os ditos anos: João Nogueira e Eduardo Campos. Verifica-se que a modernidade acaba por transformar as práticas fúnebres e cada um desses memorialistas observa essas modificações através de uma óptica própria

    On the Effects of Quantum Decoherence in a Future Supernova Neutrino Detection

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    Quantum decoherence effects in neutrinos, described by the open quantum systems formalism, serve as a gateway to explore potential new physics, including quantum gravity. Previous research extensively investigated these effects across various neutrino sources, imposing stringent constraints on the spontaneous loss of coherence. In this study, we demonstrate that even within the Supernovae environment, where neutrinos are released as incoherent states, quantum decoherence could influence the flavor equipartition of 3ν3\nu mixing. Additionally, we examine the potential energy dependence of quantum decoherence parameters (Γ=Γ0(E/E0)n\Gamma = \Gamma_0 (E/E_0)^n) with different power laws (n=0,2,5/2n = 0, 2, 5/2). Our findings indicate that future-generation detectors (DUNE, Hyper-K, and JUNO) can significantly constrain quantum decoherence effects under different scenarios. For a Supernova located 10 kpc away from Earth, DUNE could potentially establish 3σ3\sigma bounds of Γ6.2×1014\Gamma \leq 6.2 \times 10^{-14} eV in the normal mass hierarchy (NH) scenario, while Hyper-K could impose a 2σ2\sigma limit of Γ3.6×1014\Gamma \leq 3.6 \times 10^{-14} eV for the inverted mass hierarchy (IH) scenario with n=0n=0 - assuming no energy exchange between the neutrino subsystem and non-standard environment ([H,Vp]=0[H,V_p] = 0). These limits become even more restrictive for a closer Supernova. When we relax the assumption of energy exchange ([H,Vp]0[H,V_p] \neq 0), for a 10 kpc SN, DUNE can establish a 3σ3\sigma limit of Γ84.2×1028\Gamma_8 \leq 4.2 \times 10^{-28} eV for NH, while Hyper-K could constrain Γ81.3×1027\Gamma_8 \leq 1.3 \times 10^{-27} eV for IH (n=0n=0) with 2σ2\sigma, representing the most stringent bounds reported to date. Furthermore, we examine the impact of neutrino loss during propagation for future Supernova detection

    SN1987A neutrino burst: limits on flavor conversion

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    In this paper, we revisit the SN1987A neutrino data to see its constraints on flavor conversion. We are motivated by the fact that most works that analyze this data consider a specific conversion mechanism, such as the MSW (Mikheyev-Smirnov-Wolfenstein) effect, although flavor conversion is still an open question in supernovae due to the presence of neutrino-neutrino interactions. In our analysis, instead of considering a specific conversion mechanism, we let the electron antineutrino survival probability PeeP_{\overline{e}\overline{e}} be a free parameter. We fit the data from Kamiokande-II, Baksan, and IMB detected spectrum with two classes of models: time-integrated and time-dependent. For the time-integrated model, it is not possible to put limits above 1σ1\sigma (68% confidence level) on the survival probability. The same happens for the time-dependent model when cooling is the only mechanism of antineutrino emission. However, for models considering an accretion phase, Pee0P_{\overline{e}\overline{e}}\sim0 is strongly rejected, showing a preference for the existence of an accretion component in the detected antineutrino flux, and a preference for normal mass ordering when only the MSW is present.Comment: 13 pages,10 figures. Version Accepted for publication. Some updates were made in the analysis with no significant deviations from previous result
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