8,028 research outputs found

    One gluon, two gluon: multigluon production via high energy evolution

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    We develop an approach for calculating the inclusive multigluon production within the JIMWLK high energy evolution. We give a formal expression of multigluon cross section in terms of a generating functional for arbitrary number of gluons nn. In the dipole limit the expression simplifies dramatically. We recover the previously known results for single and double gluon inclusive cross section and generalize those for arbitrary multigluon amplitude in terms of Feynman diagramms of Pomeron - like objects coupled to external rapidity dependent field s(η)s(\eta). We confirm the conclusion that the AGK cutting rules in general are violated in multigluon production. However we present an argument to the effect that for doubly inclusive cross section the AGK diagramms give the leading contribution at high energy, while genuine violation only occurs for triple and higher inclusive gluon production. We discuss some general properties of our expressions and suggest a line of argument to simplify the approach further.Comment: 32 pages, one reference corrected. to appear in JHE

    Ginzburg-Landau Expansion and the Slope of the Upper Critical Field in Disordered Superconductors with Anisotropic Pairing

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    It is demonstrated that the slope of the upper critical field dHc2/dTTc|dH_{c2}/dT|_{T_{c}} in superconductors with dd-wave pairing drops rather fast with concentration of normal impurities, while in superconductors with anisotropic ss-wave pairing dHc2/dTTc|dH_{c2}/dT|_{T_{c}} grows, and in the limit of strong disorder is described by the known dependences of the theory of ``dirty'' superconductors. This allows to use the measurements of Hc2H_{c2} in disordered superconductors to discriminate between these different types of pairing in high-temperature and heavy-fermion superconductors.Comment: 7 pages, 5 figures, RevTeX 3.0, 4 Postscript figures attached; Submitted to JETP Letter

    Multimuons events and primary composition

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    Nucleon decay detectors at large depths offers now a total area larger than 1000 sq m to registrate muons of energy exceeding 1 TeV. Near complete high energy muon families are detected in those arrays. An extensive 3D Monte-Carlo simulation was conducted in view to understand the spatial distribution of those events and the possible link with elementary act or primary composition. As pion or kaon parents have a very small decay probability at so high energy, multimuon phenomena occurs at high altitude where the atmospheric density is small after the most energetic collisions

    Measurement of the η\eta -η\eta' mixing angle in π\pi^{-} and KK^{-} beams with GAMS-4π4\pi Setup

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    The results of mixing angle measurement for η\eta', η\eta mesons generated in charge exchange reactions with π\pi^{-} and KK^{-} beams are preseneted. When the η\eta', η\eta mesons are described in nonstrange(NS)--strange(S) quark basis the π\pi^{-} and KK^{-} beams allow to study ηq>|\eta_{q}> and ηs>|\eta_{s}> parts of the meson wave function. The cross section ratio at t=0t'=0 (GeV/c)2^{2} in the π\pi^{-} beam is Rπ(η/η)=0.56±0.04R_{\pi}(\eta'/\eta)= 0.56 \pm 0.04, results in mixing angle ϕP=(36.8±1.)o\phi_{P} = (36.8 \pm 1.)^{o} . For KK^{-} beam the ratio is RK(η/η)=1.30±0.16R_{K}(\eta'/\eta)= 1.30 \pm 0.16. It was found that gluonium content in η\eta' is sin2ψG=0.15±0.06\sin^{2}\psi_{G}= 0.15 \pm 0.06. The experiment was carried out with GAMS-4π\pi Setup.Comment: 6 pages, 4 figures, 1 table, to be submitted in European physical journal C. Minor changes, the Bibliography extende
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