4,463 research outputs found

    Revising the Solution of the Neutrino Oscillation Parameter Degeneracies at Neutrino Factories

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    In the context of neutrino factories, we review the solution of the degeneracies in the neutrino oscillation parameters. In particular, we have set limits to sin22θ13\sin^2 2\theta_{13} in order to accomplish the unambiguous determination of θ23\theta_{23} and δ\delta. We have performed two different analysis. In the first, at a baseline of 3000 km, we simulate a measurement of the channels νeνμ\nu_e\to\nu_\mu, νeντ\nu_e\to\nu_\tau and νˉμνˉμ\bar{\nu}_\mu\to\bar{\nu}_\mu, combined with their respective conjugate ones, with a muon energy of 50 GeV and a running time of five years. In the second, we merge the simulated data obtained at L=3000 km with the measurement of νeνμ\nu_e\to\nu_\mu channel at 7250 km, the so called 'magic baseline'. In both cases, we have studied the impact of varying the ντ\nu_\tau detector efficiency-mass product, (ϵντ×Mτ)(\epsilon_{\nu_\tau}\times M_\tau), at 3000 km, keeping unchanged the νμ\nu_\mu detector mass and its efficiency. At L=3000 km, we found the existance of degenerate zones, that corresponds to values of θ13\theta_{13}, which are equal or almost equal to the true ones. These zones are extremely difficult to discard, even when we increase the number of events. However, in the second scenario, this difficulty is overcomed, demostrating the relevance of the 'magic baseline'. From this scenario, the best limits of sin22θ13\sin^2 2\theta_{13}, reached at 3σ3\sigma, for sin22θ23=0.95\sin^2 2\theta_{23}=0.95, 0.975 and 0.99 are: 0.008, 0.015 and 0.045, respectively, obtained at δ=0\delta=0, and considering (ϵντ×Mτ)125(\epsilon_{\nu_\tau}\times M_\tau) \approx 125, which is five times the initial efficiency-mass combination.Comment: 40 pages, 18 figures; added references, corrected typos, updated Eq (15c

    Solid flow drives surface nanopatterning by ion-beam irradiation

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    Ion Beam Sputtering (IBS) is known to produce surface nanopatterns over macroscopic areas on a wide range of materials. However, in spite of the technological potential of this route to nanostructuring, the physical process by which these surfaces self-organize remains poorly under- stood. We have performed detailed experiments of IBS on Si substrates that validate dynamical and morphological predictions from a hydrodynamic description of the phenomenon. Our results elucidate flow of a nanoscopically thin and highly viscous surface layer, driven by the stress created by the ion-beam, as a description of the system. This type of slow relaxation is akin to flow of macroscopic solids like glaciers or lead pipes, that is driven by defect dynamics.Comment: 12 pages, 4 figure
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