2,694 research outputs found

    Large Angle Hadron Correlations from Medium-Induced Gluon Radiation

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    Final state medium-induced gluon radiation in ultradense nuclear matter is examined and shown to favor large angle emission when compared to vacuum bremsstrahlung due to the suppression of collinear gluons. Perturbative expression for the contribution of its hadronic fragments to the back-to-back particle correlations is derived. It is found that in the limit of large jet energy loss gluon radiation determines the yield and angular distribution of | Delta phi | > Pi/2 di-hadrons to transverse momenta pT2 of the associated particles. Clear transition from enhancement to suppression of the away-side hadron correlations is established at moderate pT2 and its experimentally accessible features are predicted versus the trigger particle momentum pT1.Comment: 5 pages, 3 figures. Figures 1 and 2 and some of the text revised. Footnote added. As published in Phys. Lett.

    Jet quenching in relativistic heavy ion collisions

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    Parton propagation in dense nuclear matter results in elastic, inelastic and coherent multiple soft scattering with the in-medium color charges. Such scattering leads to calculable modifications of the hadron production cross section that is evaluated in the framework of the perturbative QCD factorization approach. Final state medium-induced gluon bremsstrahlung is arguably the most efficient way of suppressing large transverse momentum particle production in nucleus-nucleus collisions. The observed hadronic attenuation, known as jet quenching, can be related to the properties of the medium, such as density and temperature, and carries valuable information about the early stages of heavy ion reactions. Non-Abelian energy loss in the quark-gluon plasma can be studied in much greater detail through the modification of the two particle back-to-back correlations. Perturbative calculations give good description of the redistribution of the lost energy in lower transverse momentum particles and predict significant increase of the correlation width of away-side di-hadrons. In contrast, energy loss in cold nuclear matter was found to be small but for large values of Feynman-x is expected to complement the dynamical higher twist shadowing in experimentally observable forward rapidity hadron suppression.Comment: Invited plenary talk at the V-th international conference on the physics and astrophysics of the quark-gluon plasma. 8 pages, 4 figure

    Quantitative features of multifractal subtleties in time series

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    Based on the Multifractal Detrended Fluctuation Analysis (MFDFA) and on the Wavelet Transform Modulus Maxima (WTMM) methods we investigate the origin of multifractality in the time series. Series fluctuating according to a qGaussian distribution, both uncorrelated and correlated in time, are used. For the uncorrelated series at the border (q=5/3) between the Gaussian and the Levy basins of attraction asymptotically we find a phase-like transition between monofractal and bifractal characteristics. This indicates that these may solely be the specific nonlinear temporal correlations that organize the series into a genuine multifractal hierarchy. For analyzing various features of multifractality due to such correlations, we use the model series generated from the binomial cascade as well as empirical series. Then, within the temporal ranges of well developed power-law correlations we find a fast convergence in all multifractal measures. Besides of its practical significance this fact may reflect another manifestation of a conjectured q-generalized Central Limit Theorem

    Sublingual grass allergen tablet immunotherapy provides sustained clinical benefit with progressive immunologic changes over 2 years

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    Background: This is an interim analysis of a randomized, double-blind, placebo-controlled phase III trial with 3 years of daily treatment with grass tablet immunotherapy (GRAZAX; ALK-Abello A/S, Horsholm, Denmark) or placebo, followed by 2 years of follow-up to assess the persistent efficacy. Objective: We sought to evaluate the efficacy and safety of specific immunotherapy with grass allergen tablets compared with placebo after treatment covering 2 consecutive grass pollen seasons. Methods: The interim analyses included 351 adult participants with moderate-to-severe allergic rhinoconjunctivitis caused by grass pollen. Participants were treated with active (n = 189) or placebo (n = 162) tablets for an average of 22 months. All participants were allowed to use symptomatic rescue medication. Results: The primary efficacy analysis showed highly significant mean reductions of 36% in rhinoconjunctivitis symptom score (P Conclusion: Grass allergen tablet immunotherapy showed progressive immunologic changes and highly significant efficacy over 2 years of continued treatment

    Jet properties from π±\pi^{\pm} - h±h^{\pm} correlation in p+pp+p and dd+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We review recent results on the charged pion - charged hadron correlation in p+pp+p and dd + Au collisions as measured by the PHENIX Collaboration. Properties of di-jet system, such as the jet shape, associated hadron yield per trigger pion, and the underlying event are extracted statistically from the π±−h±\pi^{\pm}-h^{\pm} correlation function in Δϕ\Delta\phi and Δη\Delta\eta. For jet triggered with high pTp_T pions (pT>5p_T>5 GeV/c), no apparent differences in the jet properties are seen between p+pp+p and dd + Au.Comment: Proceeding for Correlation and Fluctuation Workshop at MIT (April 2005), 11 pages, 17 figures, update a couple of formula
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