11,268 research outputs found

    Lambda polarization in pp -> p\Lambda K^+ \pi^+\pi^-\pi^+\pi^-

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    We show that there is a correlation between the invariant mass of the produced \Lambda K^+, \Lambda K^+\pi^+\pi^- or \Lambda K^+ \pi^+\pi^-\pi^+\pi^- system in the exclusive reaction pp\to p\Lambda K^+\pi^+\pi^-\pi^+\pi^- and the longitudinal or transverse momentum of Λ\Lambda. Together with the longitudinal and transverse momentum dependence of Lambda polarization observed in inclusive reactions, such a correlation implies a dependence of Lambda polarization on these invariant masses. The qualitative features of this dependence are consistent with the recent observation by E766 collaboration at BNL. A quantitative estimation has been made using an event generator for pppp collisions. A detailed comparison with the data is made.Comment: 10 pages with 3 figures, submitted to J. Phys.

    Relativistic J-matrix method

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    The relativistic version of the J-matrix method for a scattering problem on the potential vanishing faster than the Coulomb one is formulated. As in the non-relativistic case it leads to a finite algebraic eigenvalue problem. The derived expression for the tangent of phase shift is simply related to the non-relativistic case formula and gives the latter as a limit case. It is due to the fact that the used basis set satisfies the ``kinetic balance condition''.Comment: 21 pages, RevTeX, accepted for publication in Phys. Rev.

    Finite-Volume Scaling of the Wilson-Dirac Operator Spectrum

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    The microscopic spectral density of the Hermitian Wilson-Dirac operator is computed numerically in quenched lattice QCD. We demonstrate that the results given for fixed index of the Wilson-Dirac operator can be matched by the predictions from Wilson chiral perturbation theory. We test successfully the finite volume and the mass scaling predicted by Wilson chiral perturbation theory at fixed lattice spacing.Comment: 10 pages, 11 figures, version to appear in PR

    Влияние горнодобывающей промышленности на регионы России

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    В данной статье рассмотрено влияние горнодобывающей промышленности на экологическую ситуацию регионов России, к ним относится: Кузнецкий, Иркутский, КанскоАчинский, Южно-Якутский и Донецкий каменноугольные бассейны. Проанализированы последствия горной добычи. Выявлены методы борьбы с загрязнением окружающей среды. Установлено, что существующих методов недостаточно, важен человеческий фактор. This article discusses the impact of the mining industry on the environmental situation ofthe regions of Russia, these include: Kuznetsk, Irkutsk, Kansk-Achinsk, South Yakutia and Donetsk coal basin.Analyzed the effects of mining. Identified methods of dealing with environmental pollution. It was foundthat existing methods is not enough, the human factor is important

    Extracting FπF_\pi from small lattices: unquenched results

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    We calculate the response of the microscopic Dirac spectrum to an imaginary isospin chemical potential for QCD with two dynamical flavors in the chiral limit. This extends our previous calculation from the quenched to the unquenched theory. The resulting spectral correlation function in the ϵ\epsilon-regime provides here, too, a new and efficient way to measure FπF_\pi on the lattice. We test the method in a hybrid Monte Carlo simulation of the theory with two staggered quarks.Comment: 7 pages, 5 figure

    Chiral crossover, deconfinement and quarkyonic matter within a Nambu-Jona Lasinio model with the Polyakov loop

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    We study the interplay between the chiral and the deconfinement transitions, both at high temperature and high quark chemical potential, by a non local Nambu-Jona Lasinio model with the Polyakov loop in the mean field approximation and requiring neutrality of the ground state. We consider three forms of the effective potential of the Polyakov loop: two of them with a fixed deconfinement scale, cases I and II, and the third one with a μ\mu dependent scale, case III. In the cases I and II, at high chemical potential μ\mu and low temperature TT the main contribution to the free energy is due to the Z(3)-neutral three-quark states, mimicking the quarkyonic phase of the large NcN_c phase diagram. On the other hand in the case III the quarkyonic window is shrunk to a small region. Finally we comment on the relations of these results to lattice studies and on possible common prospects. We also briefly comment on the coexistence of quarkyonic and color superconductive phases.Comment: 16 pages, 7 figures, RevTeX4. Some typos corrected, references adde

    Pion-nucleus optical potential valid up to the DELTA-resonance region

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    We present in this article an optical potential for the π\pi-nucleus interaction that can be used in various studies involving π\pi-nucleus channels. Based on earlier treatments of the low energy π\pi-nucleus optical potential, we have derived a potential expression applicable from threshold up to the Δ\Delta-resonance region. We extracted the impulse approximation form for this potential from the πN\pi-N scattering amplitude and then added to it kinematical and physical corrections. The kinematic corrections arise from transforming the impulse approximation expression from the πN\pi-N center of mass frame to the π\pi-nucleus center of mass frame, while the physical corrections arise mostly from the many-body nature of the π\pi-nucleus interaction. By taking advantage of the experimental progress in our knowledge of the πN\pi-N process, we have updated earlier treatments with parameters calculated from state-of-the-art experimental measurements.Comment: 23 pages, 12 figures. Accepted for publication in Physical Review

    The Coulomb law in the pure gauge U(1) theory on a lattice

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    We study the heavy charge potential in the Coulomb phase of pure gauge compact U(1) theory on the lattice. We calculate the static potential VW(T,R)V_W(T,{\vec R}) from Wilson loops on a 163×3216^3 \times 32 lattice and compare with the predictions of lattice perturbation theory. We investigate finite size effects and, in particular, the importance of non-Coulomb contributions to the potential. We also comment on the existence of a maximal coupling in the Coulomb phase of pure gauge U(1) theory.Comment: 14 pages. LaTeX file and 3 postscript figure
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