1,269 research outputs found

    Scaling ansatz, four zero Yukawa textures and large θ13\theta_{13}

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    We investigate 'Scaling ansatz' in the neutrino sector within the framework of type I seesaw mechanism with diagonal charged lepton and right handed Majorana neutrino mass matrices (MRM_R). We also assume four zero texture of Dirac neutrino mass matrices (mDm_D) which severely constrain the phenomenological outcomes of such scheme. Scaling ansatz and the present neutrino data allow only Six such matrices out of 126 four zero Yukawa matrices. In this scheme, in order to generate large θ13\theta_{13} we break scaling ansatz in mDm_D through a perturbation parameter and we also show our breaking scheme is radiatively stable. We further investigate CP violation and baryogenesis via leptogenesis in those surviving textures.Comment: 25 pages, 8 figures, Accepted for publication in Phys. Rev.

    Heavy Top Quark Searches in the Di-Lepton Mode at the Tevatron

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    We present the results of a detailed study of the effects of bb-tagging on the heavy top-quark signal and backgrounds for the modes of the di-lepton plus two high transverse energy jets at the Fermilab Tevatron. The general characteristics of the heavy top-quark signal events are also discussed so that a comparison can be made between bb-tagging and imposing stringent kinematical cuts to eliminate backgrounds.Comment: uses PHYZZX and TABLES macros, 10 pages, four figures not included (available by request), FERMILAB-Pub-93/105-

    Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments

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    In the overlap region, for the normal and inverted hierarchies, of the neutrino-antineutrino bi-probability space for νμνe\nu_\mu \to \nu_e appearance, we derive a simple identity between the solutions in the (sin22θ13\sin^2 2\theta_{13}, sinδ\sin \delta) plane for the different hierarchies. The parameter sin22θ13\sin^2 2\theta_{13} sets the scale of the νμνe\nu_\mu \to \nu_e appearance probabilities at the atmospheric δmatm22.4×103\delta m^2_{atm} \approx 2.4 \times 10^{-3} eV2^2 whereas sinδ\sin \delta controls the amount of CP violation in the lepton sector. The identity between the solutions is that the difference in the values of sinδ\sin \delta for the two hierarchies equals twice the value of sin22θ13\sqrt{\sin^2 2\theta_{13}} divided by the {\it critical} value of sin22θ13\sqrt{\sin^2 2\theta_{13}}. We apply this identity to the two proposed long baseline experiments, T2K and NOν\nuA, and we show how it can be used to provide a simple understanding of when and why fake solutions are excluded when two or more experiments are combined. The identity demonstrates the true complimentarity of T2K and NOν\nuA.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of Physics, ``Focus on Neutrino Physics'' issu

    On the Coupling of Gravitons to Matter

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    Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive graviton exchange, as would arise in the presence of large compact dimensions. The gauge charges are represented by flavors of dynamical scalars or fermions. This also leads to an unconventional decomposition of color and kinematics in gauge theories.Comment: RevTex, 4 page

    M\"ossbauer Antineutrinos: Recoilless Resonant Emission and Absorption of Electron Antineutrinos

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    Basic questions concerning phononless resonant capture of monoenergetic electron antineutrinos (M\"ossbauer antineutrinos) emitted in bound-state beta-decay in the 3H - 3He system are discussed. It is shown that lattice expansion and contraction after the transformation of the nucleus will drastically reduce the probability of phononless transitions and that various solid-state effects will cause large line broadening. As a possible alternative, the rare-earth system 163Ho - 163Dy is favoured. M\"ossbauer-antineutrino experiments could be used to gain new and deep insights into several basic problems in neutrino physics

    Academic Librarianship and the Redefining Scholarship Project: A Report from the Association of College and Research Libraries Task Force on Institutional Priorities and Faculty Rewards

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    At the July, 1996 Annual Conference of the American Library Association, the Board of Directors of the Association of College and Research Libraries (ACRL) appointed a task force to write a formal statement defining and describing the kind of scholarship performed by academic librarians, using as a framework the taxonomy developed by Eugene Rice and elaborated by Ernest Boyer in his 1990 book Scholarship Reconsidered: Priorities of the Professoriate.(1) The task force\u27s statement, upon approval by the ACRL Board, is intended to become part of a larger movement established by Syracuse University\u27s Center for Instructional Development, entitled the Institutional Priorities and Faculty Rewards project. The project, which is being funded by the Lilly Endowment, with support from the Fund for the Improvement of Postsecondary Education, is providing assistance to academic associations for the development and dissemination of definitions of scholarship for their disciplines. The definitions are intended to extend the range of activities recognized as scholarly for the purposes of tenure, promotion, merit, or reward system guidelines. The following is the report of the ACRL task force

    Implications of New Gallex Results for the MSW Solution of the Solar Neutrino Problem

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    We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron scattering experiments are discussed.Comment: 7 pages (plus 3 figures available upon request) UTAPHY-HEP-

    Parameter Degeneracies in Neutrino Oscillation Measurement of Leptonic CP and T Violation

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    The measurement of the mixing angle \theta_{13}, sign of \Delta m^2_{13} and the CP or T violating phase \delta is fraught with ambiguities in neutrino oscillation. In this paper we give an analytic treatment of the paramater degeneracies associated with measuring the \nu_\mu -> \nu_e probability and its CP and/or T conjugates. For CP violation, we give explicit solutions to allow us to obtain the regions where there exist two-fold and four-fold degeneracies. We calculate the fractional differences, \Delta \theta / \bar{\theta}, between the allowed solutions which may be used to compare with the expected sensitivities of the experiments. For T violation we show that there is always a complete degeneracy between solutions with positive and negative \Delta m^2_{13} which arises due to a symmetry and cannot be removed by observing one neutrino oscillation probability and its T conjugate. Thus, there is always a four fold parameter degeneracy apart from exceptional points. Explicit solutions are also given and the fractional differences are computed. The bi-probability CP/T trajectory diagrams are extensively used to illuminate the nature of the degeneracies.Comment: 35 pages, Latex, 11 postscript figures, minor correction
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