10,328 research outputs found

    Three-Neutrino MSW Effect and the LNW Mass Matrix

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    We review recent work on analytical solutions to the MSW equations for three neutrino flavours, for exponential and linear potentials. An application to a particular mass matrix is also discussed. The three neutrino masses are determined, respectively, to be 0.001--0.004, and roughly 0.01 and 0.05 eV.Comment: 7 pages, presented at Scandinavian Neutrino Workshop, Uppsala, February 8-10, 2001, to appear in the proceedings, Physica Scripta. Conference info at http://www3.tsl.uu.se/~damet/neutrino/first.htm

    Quantum memory: Write, read and reset

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    A model is presented for the quantum memory, the content of which is a pure quantum state. In this model, the fundamental operations of writing on, reading, and resetting the memory are performed through scattering from the memory. The requirement that the quantum memory must remain in a pure state after scattering implies that the scattering is of a special type, and only certain incident waves are admissible. An example, based on the Fermi pseudo-potential in one dimension, is used to demonstrate that the requirements on the scattering process are consistent and can be satisfied. This model is compared with the commonly used model for the quantum memory; the most important difference is that the spatial dimensions and interference play a central role in the present model.Comment: RevTeX4, 7 pages, no figure

    Scalar Quarks at the Large Hadron Collider

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    The properties of scalar quarks are studied, especially the formation of fermionic mesons with an anti-quark. On the basis of this theoretical investigation together with the experimental data, both from last year and from this year, of the ATLAS Collaboration and the CMS Collaboration at the Large Hadron Collider, it is proposed that the standard model of Glashow, Weinberg, and Salam should be augmented by scalar quarks, scalar leptons, and additional fermions. If these scalar quarks and scalar leptons are in one-to-one correspondence with the ordinary quarks and ordinary leptons, either in number or in the degrees of freedom, then there may be a fermion-boson symmetry. The fermion-boson symmetry obtained this way is of a different nature from that of supersymmetry.Comment: 7 pages, 1 figur

    Impact-picture predictions for the γγ\gamma\gamma total cross section at LEP

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    We show that the rising total cross section σ(γγ→hadrons)\sigma(\gamma\gamma \to hadrons) recently observed by the L3 and OPAL Collaborations at LEP are fully consistent with the impact-picture for high-energy scattering. The impact picture is then used to predict this total cross section at higher energies. These experimental results confirm once more the success of the theoretical approach, which predicted for the first time, nearly thirty years ago, the universal increase of total cross sections at high energies.Comment: 5 pages, Latex, 1 figure. Revised versio

    Mikheyev-Smirnov-Wolfenstein Effect for Linear Electron Density

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    When the electron density is a linear function of distance, it is known that the MSW equations for two neutrino species can be solved in terms of known functions. It is shown here that more generally, for any number of neutrino species, these MSW equations can be solved exactly in terms of single integrals. While these integrals cannot be expressed in terms of known functions, some of their simple properties are obtained. Application to the solar neutrino problem is briefly discussed.Comment: 14 page

    Do we understand near-forward elastic scattering up to TeV energies?

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    In 1970, on purely theoretical grounds, all total hadronic total cross sections were predicted to increase without limit for higher and higher energies. This was contrary to the conventional belief at that time. In 1978, an accurate phenomenological model was formulated for the case of proton-proton and antiproton-proton interactions. The parameters for this model were slightly improved in 1984 using the additional available experimental data. Since then, for thirty years these parameters have not changed. This development, including especially the difficult task of formulating this phenomenological model and the comparison of the predictions of this model with later experimental results, is summarized.Comment: 14 pages, 6 figures, Contribution to the special issue of the International Journal of Modern Physics A on "Elastic and diffractive scattering" coordinated by Christophe Royo

    Impact picture for near-forward elastic scattering up to LHC energies

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    We will recall the main feaatures of an accurate phenomenological model to describe successfully near-forward elastic scattering in a wide energy range, including ISR, SPS and Tevatron colliders. A large step in energy domain is accomplished with the LHC collider, presently running, giving the opportunity to confront the new data with the predictions of our theoretical approach.Comment: 4 pages, 3 figures, Invited talk presented by Jacques Soffer at DIFFRACTION 2014, September 10 - 15, 2014, Primosten, Croatia (To be published in the AIP Conference Proceedings

    MEMS flow sensors for nano-fluidic applications

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    This paper presents micromachined thermal sensors for measuring liquid flow rates in the nanoliter-per-minute range. The sensors use a boron-doped polysilicon thinfilm heater that is embedded in the silicon nitride wall of a microchannel. The boron doping is chosen to increase the heater’s temperature coefficient of resistance within tolerable noise limits, and the microchannel is suspended from the substrate to improve thermal isolation. The sensors have demonstrated a flow rate resolution below 10 nL/min, as well as the capability for detecting micro bubbles in the liquid. Heat transfer simulation has also been performed to explain the sensor operation and yielded good agreement with experimental data
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