5,226 research outputs found

    Electromagnetic Form Factors and the Hypercentral CQM

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    New results about the electromagnetic form factors of the nucleon are obtained with a semirelativistic version of the hypercentral constituent quark model (hCQM) and a relativistic current. The complex structure of the constituent quarks is taken into account implicitly by means of phenomenological constituent quark form factors. We obtain a detailed reproduction of the experimental data up to 5GeV25 GeV^2, moreover our findings about constituent quark root mean square radii are of the same order than the recent ones obtained analyzing the proton structure functions.Comment: 11 pages, 4 figure

    Why Tau First?

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    Electron neutrino has been the first neutral lepton to be foreseen and discovered last century. The un-ordered muon and its neutrino arose later by cosmic rays. The tau discover, the heaviest, the most unstable charged lepton, was found surprisingly on 1975. Its neutrino was hardly revealed just on 2000. So why High Energy Neutrino Astronomy should rise first via tau neutrino, the last, the most rare one? The reasons are based on a chain of three favorable coincidences found last decade: the neutrino masses and their flavor mixing, the UHECR opacity on Cosmic Black Body (GZK cut off on BBR), the amplified tau air-shower decaying in flight. Indeed guaranteed UHE GZK tau neutrinos, feed by muon mixing, while skimming the Earth might lead to boosted UHE tau, mostly horizontal ones. These UHE lepton decay in flight are spread, amplified, noise free Air-Shower: a huge event for an unique particle. To be observed soon: within Auger sky, in present decade. Its discover may sign of the first tau appearance.Comment: 8 pages, 4 figure

    Ultra High Energy Neutrino-Relic Neutrino Interactions In Dark Halos to Solve Infrared-Tev And GZK Cut-Off

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    Ultra High Energy Neutrino scattering on Relic Light Neutrinos in Dark Galactic or Local Group lead to Z and WW,ZZ showering: the nucleon component of the shower may overcome the GZK cut-off while the electro-magnetic tail at TeVs up to EeVs energy may solve the Infrared-TeV cut-off in a natural way. Different Gamma TeV puzzles may find a solution within this scenario: new predictions on UHECR spectra in future data are derived.Comment: 4 pages, 3 figures, 2 tables ICRC 2001 HE 3.6 Dark Matter - German

    Single Spin Asymmetries in Semi-Inclusive Electroproduction: Access to Transversity

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    We discuss the quark transversity distribution function and a possible way to access it through the measurement of single spin azimuthal asymmetry in semi-inclusive single pion electroproduction on a transversely polarized target.Comment: 5 pages, Latex using aipproc.sty (included), to appear in proceedings of "Second Workshop on Physics with an Electron Polarized Light Ion Collider", Sept. 14-16, 2000, MIT, Cambridge, US

    Using the Alpha Geodesic Distance in Shapes K-Means Clustering

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    This paper is based mainly on the relevant work [1]. In that paper the authors studied the problem of clustering of different shapes using Information Geometry tools including, among others, the Fisher Information and the resulting distance. Here we are using the same methods but for the geodesics of the alpha connection for three different values of the alpha parameter
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