3,768 research outputs found

    NOE: a neutrino experiment for the CERN-Gran Sasso Long Base line project

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    The project of a large underground experiment (NOE) devoted to long baseline neutrino oscillation measurement is presentedComment: 7 pages, 9 figures, Talk at 5th International Workshop on Tau Lepton Physics (TAU98), To be published in Nucl. Phys. B, Proc. Supp

    An infrared origin of leptonic mixing and its test at DeepCore

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    Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.Comment: 14 pages, 1 figure; version to appear in Int.J.Mod.Phys.

    A JKO splitting scheme for Kantorovich-Fisher-Rao gradient flows

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    In this article we set up a splitting variant of the JKO scheme in order to handle gradient flows with respect to the Kantorovich-Fisher-Rao metric, recently introduced and defined on the space of positive Radon measure with varying masses. We perform successively a time step for the quadratic Wasserstein/Monge-Kantorovich distance, and then for the Hellinger/Fisher-Rao distance. Exploiting some inf-convolution structure of the metric we show convergence of the whole process for the standard class of energy functionals under suitable compactness assumptions, and investigate in details the case of internal energies. The interest is double: On the one hand we prove existence of weak solutions for a certain class of reaction-advection-diffusion equations, and on the other hand this process is constructive and well adapted to available numerical solvers.Comment: Final version, to appear in SIAM SIM

    Neutrino mixing matrix in the 3-3-1 model with heavy leptons and A4A_4 symmetry

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    We study the lepton sector in the model based on the local gauge group SU(3)c⊗SU(3)L⊗U(1)XSU(3)_c\otimes SU(3)_L\otimes U(1)_X which do not contain particles with exotic electric charges. The seesaw mechanism and discrete A4A_4 symmetry are introduced into the model to understand why neutrinos are especially light and the observed pattern of neutrino mixing. The model provides a method for obtaining the tri-bimaximal mixing matrix in the leading order. A non-zero mixing angle Ve3V_{e3} presents in the modified mixing matrix.Comment: 10 page

    Existence and approximation of probability measure solutions to models of collective behaviors

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    In this paper we consider first order differential models of collective behaviors of groups of agents based on the mass conservation equation. Models are formulated taking the spatial distribution of the agents as the main unknown, expressed in terms of a probability measure evolving in time. We develop an existence and approximation theory of the solutions to such models and we show that some recently proposed models of crowd and swarm dynamics fit our theoretic paradigm.Comment: 31 pages, 1 figur

    Nuclear Track Detectors. Searches for Exotic Particles

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    We used Nuclear Track Detectors (NTD) CR39 and Makrofol for many purposes: i) Exposures at the SPS and at lower energy accelerator heavy ion beams for calibration purposes and for fragmentation studies. ii) Searches for GUT and Intermediate Mass Magnetic Monopoles (IMM), nuclearites, Q-balls and strangelets in the cosmic radiation. The MACRO experiment in the Gran Sasso underground lab, with ~1000 m^2 of CR39 detectors (plus scintillators and streamer tubes), established an upper limit for superheavy GUT poles at the level of 1.4x10^-16 cm^-2 s^-1 sr^-1 for 4x10^-5 <beta<1. The SLIM experiment at the high altitude Chacaltaya lab (5230 m a.s.l.), using 427 m^2 of CR39 detectors exposed for 4.22 y, gave an upper limit for IMMs of ~1.3x10^-15 cm^-2 s^-1 sr^-1. The experiments yielded interesting upper limits also on the fluxes of the other mentioned exotic particles. iii) Environmental studies, radiation monitoring, neutron dosimetry.Comment: Talk given at "New Trends In High-Energy Physics" (experiment, phenomenology, theory) Yalta, Crimea, Ukraine, September 27-October 4, 200

    Search for nuclearites with the SLIM detector

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    We discuss the properties of cosmic ray nuclearites, from the point of view of their search with large nuclear track detector arrays exposed at different altitudes, in particular with the SLIM experiment at the Chacaltaya high altitude lab (5290 m a.s.l.). We present calculations concerning their propagation in the Earth atmosphere and discuss their possible detection with CR39 and Makrofol nuclear track detectors.Comment: 11 pages, 6 figure
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