148,969 research outputs found

    Seismic anisotropy of Precambrian lithosphere : Insights from Rayleigh wave tomography of the eastern Superior Craton

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    The seismic data used in this study are freely available from the CNDC (Canadian National Data Centre for Earthquake Seismology and Nuclear Explosion Monitoring) and IRIS DMC (Data Management Center) via their data request tools. The Leverhulme Trust (grant RPG-2013-332) and National Science Foundation are acknowledged for financial support. L.P. is supported by Janet Watson Imperial College Department Scholarship and the Romanian Government Research Grant NUCLEU. F.D. is supported by NSERC through the Discovery Grants and Canada Research Chairs program. We also thank two anonymous reviewers and the Associate Editor for insightful comments that helped improve the manuscript.Peer reviewedPublisher PD

    Two Higgs Bi-doublet Left-Right Model With Spontaneous P and CP Violation

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    A left-right symmetric model with two Higgs bi-doublet is shown to be a consistent model for both spontaneous P and CP violation. The flavor changing neutral currents can be suppressed by the mechanism of approximate global U(1) family symmetry. We calculate the constraints from neural KK meson mass difference ΔmK\Delta m_K and demonstrate that a right-handed gauge boson W2W_2 contribution in box-diagrams with mass well below 1 TeV is allowed due to a cancellation caused by a light charged Higgs boson with a mass range 150∌300150 \sim 300 GeV. The W2W_2 contribution to Ï”K\epsilon_K can be suppressed from appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa matrix. The model is also found to be fully consistent with B0B^0 mass difference ΔmB\Delta m_B, and the mixing-induced CP violation quantity sin⁥2ÎČJ/ψ\sin2\beta_{J/\psi}, which is usually difficult for the model with only one Higgs bi-doublet. The new physics beyond the standard model can be directly searched at the colliders LHC and ILC.Comment: 25 pages, 6 figures, typos corrected, 1 figure added, published versio

    Local moment, itinerancy and deviation from Fermi liquid behavior in Nax_xCoO2_2 for 0.71≀x≀0.840.71 \leq x \leq 0.84

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    Here we report the observation of Fermi surface (FS) pockets via the Shubnikov de Haas effect in Nax_xCoO2_2 for x=0.71x = 0.71 and 0.84, respectively. Our observations indicate that the FS expected for each compound intersects their corresponding Brillouin zones, as defined by the previously reported superlattice structures, leading to small reconstructed FS pockets, but only if a precise number of holes per unit cell is \emph{localized}. For 0.71≀x<0.750.71 \leq x < 0.75 the coexistence of itinerant carriers and localized S=1/2S =1/2 spins on a paramagnetic triangular superlattice leads at low temperatures to the observation of a deviation from standard Fermi-liquid behavior in the electrical transport and heat capacity properties, suggesting the formation of some kind of quantum spin-liquid ground state.Comment: 4 pages, 4 figure

    An Analysis of the Decay B→D∗XℓΜˉℓB \rightarrow D^* X \ell \bar\nu_\ell with Predictions from Heavy Quark and Chiral Symmetry

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    This paper considers the implications of the heavy quark and chiral symmetries for the semi-leptonic decay B→D∗XℓΜˉℓB \rightarrow D^* X \ell \bar \nu_\ell. The general kinematic analysis for decays of the form {\sl pseudoscalar meson →\rightarrow vector meson ++ pseudoscalar meson ++ lepton ++ anti-lepton} is presented. This formalism is applied to the above exclusive decay which allows the differential decay rate to be expressed in a form that is ideally suited for the experimental determination of the different form factors for the process through angular distribution measurements. Heavy quark and chiral symmetry predictions for the form factors are presented, and the differential decay rate is calculated in the kinematic region where chiral perturbation theory is valid.Comment: 15 pages, uses jytex.tex and tables.tex; 3 figures not included but available on reques

    Generalized Heisenberg algebras and k-generalized Fibonacci numbers

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    It is shown how some of the recent results of de Souza et al. [1] can be generalized to describe Hamiltonians whose eigenvalues are given as k-generalized Fibonacci numbers. Here k is an arbitrary integer and the cases considered by de Souza et al. corespond to k=2.Comment: 8 page

    The Sivashinsky equation for corrugated flames in the large-wrinkle limit

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    Sivashinsky's (1977) nonlinear integro-differential equation for the shape of corrugated 1-dimensional flames is ultimately reducible to a 2N-body problem, involving the 2N complex poles of the flame slope. Thual, Frisch & Henon (1985) derived singular linear integral equations for the pole density in the limit of large steady wrinkles (N≫1)(N \gg 1), which they solved exactly for monocoalesced periodic fronts of highest amplitude of wrinkling and approximately otherwise. Here we solve those analytically for isolated crests, next for monocoalesced then bicoalesced periodic flame patterns, whatever the (large-) amplitudes involved. We compare the analytically predicted pole densities and flame shapes to numerical results deduced from the pole-decomposition approach. Good agreement is obtained, even for moderately large Ns. The results are extended to give hints as to the dynamics of supplementary poles. Open problems are evoked
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