160 research outputs found

    Search for Sterile Neutrinos at OPERA and other Long--Baseline Experiments

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    The OPERA experiment at the CNGS beam has observed muon to tau neutrino oscillations in the atmospheric sector. Based on this result new limits on the mixing parameters of a massive sterile neutrino may be set. Preliminary results of the analysis done in the 3+1 neutrino framework are here presented. An update of the search for sterile neutrinos in the νμ→νe\nu_{\mu} \rightarrow \nu_e channel is also given. The status of the searches for sterile neutrinos performed at other Long--Baseline experiments (MINOS at NuMI beam and SuperK with the atmospheric flux) is also briefly recalled. Finally, some personal perspectives are discussed.Comment: 7 pages, Proceedings EPS2015, Vienna 22-29 July 201

    The next challenge for neutrinos: the mass ordering

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    Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long--standing investigation of new physics beyond the Standard Model. This is also supported by the recent change of perspectives in neutrino researches since the discovery period is almost over and we are entering the phase of precise measurements. Despite the limited statistics collected for some variables, the three--flavour neutrino framework seems well strengthening. However some relevant pieces of this framework are still missing. The amount of a possible CP violation phase and the mass ordering are among the most challenging and probably those that will be known in the near future. In this paper we will discuss these two correlated issues and a very recent new statistical method introduced to get reliable results on the mass ordering.Comment: 10 pages, 9 figure, proceedings of the ICFNP 2016 conferenc

    A new way to determine the neutrino mass hierarchy at reactors

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    The determination of the neutrino mass ordering is currently pursued by several experiments and proposals. A very challenging one is its evaluation from reactor experiments based on the tiny interference effect between the Δm312\Delta m^2_{31} and Δm322\Delta m^2_{32} oscillations. Current analyses require several years of data taking and an extreme energy resolution to achieve anyhow less than 5 σ\sigma. Referring to the JUNO experimental conditions we developed a completely new technique that would provide a robust 5 σ\sigma measurement in less than six years of running. The two orderings could be discriminated at the price of allowing for two different values of Δm312\Delta m^2_{31}. This degeneracy on Δm312\Delta m^2_{31} (around 12×10−512\times 10^{-5} eV2^2) can however be measured at an unprecedented accuracy of much less than 1\%, i.e. 10−510^{-5} eV2^2, within the same analysis. Analogies with the usual χ2\chi^2 analysis, where the Δm312\Delta m^2_{31} degeneracy is much more important, are discussed. Evaluation and inclusion of systematic errors and backgrounds have been performed, the most relevant among them being the addition of the two remote reactor plants 250 km away. Baselines of each contributing reactor core and its spatial resolution have been taken into account. Possible results after two years of running and the foreseen initially-reduced available reactor power have been studied, too. These results confirm the very positive perspectives for JUNO to determine the mass ordering in a vacuum-oscillation dominated region.Comment: 37 pages, 22 figures, in this version added one more appendix about Chi^2, formal foundation of F as optimal estimator, submitted to JHE

    An Appraisal of Muon Neutrino Disappearance at Short Baseline

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    Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long standing problem of new Physics beyond the Standard Model. The recent measurements of the third mixing angle θ13\theta_{13} in the standard mixing oscillation scenario encourage to pursue the still missing results on the leptonic CP violation and the absolute neutrino masses. However, several puzzling and incomplete measurements are in place which deserve an exhaustive evaluation and study. We will report about the present situation of the muon disappearance measurements at small L/EL/E in the context of the current CERN project to revitalize the neutrino field in Europe and the search for sterile neutrinos. We will then illustrate the achievements that a double muon spectrometer can attain in terms of discovery of new neutrino states, performing a newly developed analysis.Comment: 19 pages, 8 figures, to be published in "Advances in High Energy Physics

    Fast and simple qubit-based synchronization for quantum key distribution

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    We propose Qubit4Sync, a synchronization method for Quantum Key Distribution (QKD) setups, based on the same qubits exchanged during the protocol and without requiring additional hardware other than the one necessary to prepare and measure the quantum states. Our approach introduces a new cross-correlation algorithm achieving the lowest computational complexity, to our knowledge, for high channel losses. We tested the robustness of our scheme in a real QKD implementation

    Effect of pre-weaning solid feed and milk intake on caecal content characteristics and performance of rabbits around weaning

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    The aim of this study is to know the effect of different solid feed and milk intake during suckling on performance around weaning and on caecal content characteristics at weaning. In order to obtain different intakes of milk and solid feed, 13 litters of pregnant females (PF) inseminated the day after delivery and 14 litters of non-pregnant females (NPF) were compared. At birth the litters were equalized at eight pups and during lactation dead pups were replaced by pups of the same age from nursing does. Compared to the PF group, rabbits in the NPF group had a higher milk intake (26.0 versus 21.4 g/day; P < 0.01) and lower solid feed intake (9.1 versus 11.5 g/day; P < 0.01) between 20 and 28 days of age. No significant difference was observed between the two groups in weight gain before and post-weaning (28-49 days). At weaning, the rabbits in group PF showed higher values in caecal content (g 26.3 versus 22.6; P < 0.05) and volatile fatty acids (mmol/l 52.2 versus 43.6; P < 0.01) and lower values in empty caecal weight (g 7.18 versus 7.78; P < 0.05), C3 (6.4 versus 9.3%; P < 0.01) and C3/C4 ratio (0.39 versus 0.63; P < 0.01) than the group NPF. On the basis of the above results, it may be concluded that the quantity of solid feed and milk intake before weaning influenced the charac- teristics of the caecal content, but not the performance of rabbits around weaning

    Extending Wheeler's delayed-choice experiment to Space

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    Gedankenexperiments have consistently played a major role in the development of quantum theory. A paradigmatic example is Wheeler's delayed-choice experiment, a wave-particle duality test that cannot be fully understood using only classical concepts. Here, we implement Wheeler's idea along a satellite-ground interferometer which extends for thousands of kilometers in Space. We exploit temporal and polarization degrees of freedom of photons reflected by a fast moving satellite equipped with retro-reflecting mirrors. We observed the complementary wave-like or particle-like behaviors at the ground station by choosing the measurement apparatus while the photons are propagating from the satellite to the ground. Our results confirm quantum mechanical predictions, demonstrating the need of the dual wave-particle interpretation, at this unprecedented scale. Our work paves the way for novel applications of quantum mechanics in Space links involving multiple photon degrees of freedom.Comment: 4 figure
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