3,166 research outputs found

    Neutrino oscillograms of the Earth and CP violation in neutrino oscillations

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    An analysis of 3-flavour neutrino oscillations inside the Earth is presented in terms of the oscillograms -- contour plots of oscillation probabilities in the plane neutrino energy -- nadir angle. Special attention is paid to CP violation in neutrino oscillations in the Earth.Comment: Talk given at Neutrino Oscillations Workshop NOW2008, 3 pages, 2 figure

    Seesaw mechanism and the neutrino mass matrix

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    The seesaw mechanism of neutrino mass generation is analysed under the following assumptions: (1) minimal seesaw with no Higgs triplets, (2) hierarchical Dirac masses of neutrinos, (3) large lepton mixing primarily or solely due to the mixing in the right-handed neutrino sector, and (4) unrelated Dirac and Majorana sectors of neutrino masses. It is shown that large mixing governing the dominant channel of the atmospheric neutrino oscillations can be naturally obtained and that this constrained seesaw mechanism favours the normal mass hierarchy for the light neutrinos leading to a small Ue3U_{e3} entry of the lepton mixing matrix and a mass scale of the lightest right handed neutrino M10101011M\simeq 10^{10} - 10^{11} GeV. Any of the three main neutrino oscillation solutions to the solar neutrino problem can be accommodated. The inverted mass hierarchy and quasi-degeneracy of neutrinos are disfavoured in our scheme.Comment: LaTeX, 3 pages, no figures. Talk given at 6th International Workshop on Topics in Astroparticle and Underground Physics (TAUP 99), September 6-10, 1999, Paris, Franc

    Pontecorvo's Original Oscillations Revisited

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    We show that a left-handed neutrino νL\nu_L can oscillate into its CPCP- conjugated state νˉR\bar{\nu}_R with maximal amplitude, in direct analogy with K0Kˉ0K^0-\bar{K}^0 oscillations. Peculiarities of such oscillations under different conditions are studied.Comment: LaTeX, 14 pages, 1 figure (not included but available upon request by fax or ordinary mail), SISSA 9/93/EP, IC/93/1

    Fourier Analysis of the Parametric Resonance in Neutrino Oscillations

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    Parametric enhancement of the appearance probability of the neutrino oscillation under the inhomogeneous matter is studied. Fourier expansion of the matter density profile leads to a simple resonance condition and manifests that each Fourier mode modifies the energy spectrum of oscillation probability at around the corresponding energy; below the MSW resonance energy, a large-scale variation modifies the spectrum in high energies while a small-scale one does in low energies. In contrast to the simple parametric resonance, the enhancement of the oscillation probability is itself an slow oscillation as demonstrated by a numerical analysis with a single Fourier mode of the matter density. We derive an analytic solution to the evolution equation on the resonance energy, including the expression of frequency of the slow oscillation.Comment: 12 pages, 3 color figures, LaTeX, elsarticle.st

    Construction of Exotic Smooth Structures

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    In this article, we construct infinitley many simply connected, nonsymplectic and pairwise nondiffeomorphic 4-manifolds starting from E(n) and applying the sequence of knot surgery, ordinary blowups and rational blowdown. We also compute the Seiberg-Witten invariants of these manifolds.Comment: 10 page

    On groups of diffeomorphisms of the interval with finitely many fixed points II

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    In [6], it is proved that any subgroup of Diff+ω(I)\mathrm{Diff}_{+}^{\omega }(I) (the group of orientation preserving analytic diffeomorphisms of the interval) is either metaabelian or does not satisfy a law. A stronger question is asked whether or not the Girth Alternative holds for subgroups of Diff+ω(I)\mathrm{Diff}_{+}^{\omega }(I). In this paper, we answer this question affirmatively for even a larger class of groups of orientation preserving diffeomorphisms of the interval where every non-identity element has finitely many fixed points. We show that every such group is either affine (in particular, metaabelian) or has infinite girth. The proof is based on sharpening the tools from the earlier work [1]