12,978 research outputs found

    Oceanographic applications of the Kalman filter

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    The Kalman filter is a data-processing algorithm with a distinguished history in systems theory. Its application to oceanographic problems is in the embryo stage. The behavior of the filter is demonstrated in the context of an internal equatorial Rossby wave propagation problem

    Role of Long-Range Correlations on the Quenching of Spectroscopic Factors

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    We consider the proton and neutron quasiparticle orbits around the closed-shell 56Ni and 48Ca isotopes. It is found that large model spaces (beyond the capability of shell-model applications) are necessary for predicting the quenchings of spectroscopic factors. The particle-vibration coupling is identified as the principal mechanism. Additional correlations--due to configuration with several particle-hole excitations--are estimated using shell-model calculations and generate an extra reduction which is < ~4% for most quasiparticle states. The theoretical calculations nicely agree with (e,e'p) and heavy ion knock-out experiments. These results open a new path for a microscopic understanding of the shell-model.Comment: Minor comments added and typos corrected. Accepted for publication on Phys. Rev. Let

    The Hosotani Mechanism in Bulk Gauge Theories with an Orbifold Extra Space S^1/Z_2

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    We pursue the possibility of the scenario in which the Higgs field is identified with the extra-space component of a bulk gauge field. The space-time we take is M4^{4} ⊗\otimes S1^1/Z2_2. We show that a non-trivial Z2_2-parity assignment allows some of the extra-space component to have radiatively induced VEV, which strongly modifies the mass spectrum and gauge symmetry of the theory, realized by oribifolding. In particular we investigate the dynamical mass generation of zero-mode fermion and spontaneous gauge symmetry breaking due to the VEV. The gauge theories we adopt are a prototype model SU(2) and SU(3) model, of special interest as the realistic minimal scheme to incorporate the standard model SU(2) ×\times U(1).Comment: 16 pages 3 figure

    The LHC (CMS) Discovery Potential for Models with Effective Supersymmetry and Nonuniversal Gaugino Masses

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    We investigate squark and gluino pair production at LHC (CMS) with subsequent decays into quarks, leptons and LSP in models with effective supersymmetry where third generation of squarks is relatively light while the first two generations of squarks are heavy. We consider the general case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in (n \geq 2)jets + (m \geq 0)leptons + E^{miss}_T events depends rather strongly on the relation between LSP, second neutralino, gluino and squark masses and it decreases with the increase of LSP mass. We find that for relatively heavy gluino it is very difficult to detect SUSY signal even for light 3^{rd} generation squarks (m_{\tilde q_3}\le 1 TeV) if the LSP mass is closed to the 3^{rd} generation squark mass.Comment: 1 latex (35 pages), 4 eps (figures) file

    Charm and Bottom Quark Masses from Perturbative QCD

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    Using a new result for the first moment of the hadronic production cross section at order O(αs3){\cal O}(\alpha_s^3), and new data on the J/ψJ/\psi and ψâ€Č\psi' resonances for the charm quark, we determine the \msb masses of the charm and bottom quarks to be mˉc(mˉc)=1.295±0.015\bar{m}_c(\bar{m}_c) = 1.295 \pm 0.015 GeV and mˉb(mˉb)=4.205±0.058\bar{m}_b(\bar{m}_b) = 4.205 \pm 0.058 GeV. We assume that the continuum contribution to the sum rules is adequately described by pQCD. While we observe a large reduction of the perturbative error, the shifts induced by the theoretical input are very small. The main change in the central value of mcm_c is related to the experimental data. On the other hand, the value of mbm_b is not changed by our calculation to the assumed precision.Comment: 5 pages, 2 figures, final version as publishe

    Utilization requirements. A southern California Gas Company project SAGE report: Utilization requirements

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    Utilization requirements are given and comparisons made of two phase III SAGE (solar assisted gas energy) installations in California: (1) a retrofit installation in an existing apartment building in El Toro, and (2) an installation in a new apartment building in Upland. Such testing in the field revealed the requirements to be met if SAGE-type installations are to become commercially practical on a widespread basis in electric and gas energy usage

    The Neron-Severi group of a proper seminormal complex variety

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    We prove a Lefschetz (1,1)-Theorem for proper seminormal varieties over the complex numbers. The proof is a non-trivial geometric argument applied to the isogeny class of the Lefschetz 1-motive associated to the mixed Hodge structure on H^2.Comment: 16 pages; Mathematische Zeitschrift (2008

    Electric Dipole moments of charged leptons and lepton flavor violating interactions in the general two Higgs Doublet model

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    We calculate the electric dipole moment of electron using the experimental result of muon electric dipole moment and upper limit of the BR(\mu --> e\gamma) in the framework of the general two Higgs doublet model. Our prediction is 10^{-32} e-cm, which lies in the experimental current limits. Further, we obtain constraints for the Yukawa couplings \bar{\xi}^{D}_{N,\tau e} and \bar{\xi}^{D}_{N,\tau\mu}. Finally we present an expression which connects the BR(\tau\to \mu\gamma) and the electric dipole moment of \tau-lepton and study the relation between these physical quantities.Comment: 8 pages, 4 Figures (required epsf sty

    Pre-MS depletion, accretion and primordial 7Li

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    We reconsider the role of pre-main sequence (pre-MS) Li depletion on the basis of new observational and theoretical evidence: i) new observations of Halpha emissions in young clusters show that mass accretion could be continuing till the first stages of the MS, ii) theoretical implications from helioseismology suggest large overshooting values below the bottom of the convective envelopes. We argue here that a significant pre-MS 7Li destruction, caused by efficient overshoot mixing, could be followed by a matter accretion after 7Li depletion has ceased on MS thus restoring Li almost to the pristine value. As a test case we show that a halo dwarf of 0.85 Msun with an extended overshooting envelope starting with an initial abundance of A(Li) = 2.74 would burn Li completely, but an accretion rate of the type 1e-8xe^{-t/3e6} Msun yr−1^{-1} would restore Li to end with an A(Li) = 2.31. A self-regulating process is required to produce similar final values in a range of different stellar masses to explain the PopII Spite plateau. However, this framework could explain why open cluster stars have lower Li abundances than the pre-solar nebula, the absence of Li in the most metal poor dwarfs and a number of other features which lack of a satisfactory explanation.Comment: To be published in Memorie della Societ\`a Astronomica Italiana Supplementi Vol. 22, Proceedings of Lithium in the cosmos, Iocco F., Bonifacio P., Vangioni E., ed
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