5,618 research outputs found

    Bosonic Quartic Couplings at LEP2

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    We list the set of C and P conserving anomalous quartic vector bosons self-couplings which can be tested at LEP2 through triple vector boson production. We show how this set can be embedded in manifestly SU(2)xU(1) gauge invariant operators exhibiting an SU(2)_c global symmetry. We derive bounds on these various couplings and show the most relevant distributions that can enhance their contribution. We also find that an e+e- collider running at 500 GeV can improve the LEP2 limits by as much as three orders of magnitude.Comment: 21 pages, 7 figure

    Non-volatile bistability effect based on electrically controlled phase transition in scaled magnetic semiconductor nanostructures

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    We explore the bistability effect in a dimensionally scaled semiconductor nanostruncture consisting of a diluted magnetic semiconductor quantum dot (QD) and a reservoir of itinerant holes separated by a barrier. The bistability stems from the magnetic phase transition in the QD mediated by the changes in the hole population. Our calculation shows that when properly designed, the thermodynamic equilibrium of the scaled structure can be achieved at two different configurations; i.e., the one with the QD in a ferromagnetic state with a sufficient number of holes and the other with the depopulated QD in a paramagnetic state. Subsequently, the parameter window suitable for this bistability formation is discussed along with the the conditions for the maximum robustness/non-volatility. To examine the issue of scaling, an estimation of the bistabiity lifetime is made by considering the thermal fluctuation in the QD hole population via the spontaneous transitions. A numerical evaluation is carried out for a typical carrier-mediated magnetic semiconductor (e.g., GaMnAs) as well as for a hypothetical case of high Curie temperature for potential room temperature operation.Comment: 9 pages, 7 figure

    Environmental and economic damage from the development of oil and gas fields in the Arctic shelf of the Russian Federation

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    The aim of the paper is the development of a technique of assessment of possible ecological and economic damage to air resources during the development of offshore fields for ensuring sustainable development of the Arctic region of Russia. The use of a modified temporary method for determining the prevented environmental damage is proposed to point out the possible environmental and economic damage by Monte Carlo mathematical modelling. After calculations authors made a conclusion about the most rational method for calculating damage from the offshore Arctic oil and gas projects in the water of the Ob-Taz Bay in the Kara Sea. The practical significance of this work is that the proposed methodology can be applied to all oil and gas fields on the Arctic shelf of Russia for measuring potential damages from air pollution as well as soil and water pollution.peer-reviewe

    Energy spectrum of cascades generated by muons in Baksan underground scintillation telescope

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    Spectrum of cascades generated by cosmic ray muons underground is presented. The mean zenith angle of the muon arrival is theta=35 deg the depth approx. 1000 hg/sq cm. In cascades energy range 700 GeV the measured spectrum is in agreement with the sea-level integral muon spectrum index gamma=3.0. Some decrease of this exponent has been found in the range 4000 Gev
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