26 research outputs found

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

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    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003t0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

    High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

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    We present the measurement of non-photonic electron production at high transverse momentum (pT>p_T > 2.5 GeV/cc) in pp + pp collisions at s\sqrt{s} = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons (e++e2\frac{e^++e^-}{2}) at 3 GeV/c<pT< c < p_T <~10 GeV/cc from bottom and charm meson decays to be dσ(Be)+(BDe)dyeye=0{d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0} = 4.0±0.5\pm0.5({\rm stat.})±1.1\pm1.1({\rm syst.}) nb and dσDedyeye=0{d\sigma_{D\to e} \over dy_e}|_{y_e=0} = 6.2±0.7\pm0.7({\rm stat.})±1.5\pm1.5({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

    Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at sNN=200\sqrt{s_{NN}} = 200 GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, η/s\eta/s, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of η/s\eta/s that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

    Event-plane-dependent Dihadron Correlations With Harmonic Vn Subtraction In Au + Au Collisions At S Nn =200 Gev

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    STAR measurements of dihadron azimuthal correlations (Δφ) are reported in midcentral (20-60%) Au+Au collisions at sNN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, φs=|φt-ψEP|. The elliptic (v2), triangular (v3), and quadratic (v4) flow harmonic backgrounds are subtracted using the zero yield at minimum (ZYAM) method. The results are compared to minimum-bias d+Au collisions. It is found that a finite near-side (|Δφ|π/2) correlation shows a modification from d+Au data, varying with φs. The modification may be a consequence of path-length-dependent jet quenching and may lead to a better understanding of high-density QCD. © 2014 American Physical Society.894DOE; U.S. Department of EnergyArsene, I., (2005) Nucl. Phys. A, 757, p. 1. , (BRAHMS Collaboration), () NUPABL 0375-9474 10.1016/j.nuclphysa.2005.02. 130;Back, B.B., (2005) Nucl. Phys. 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    Greenhouse gas emission profiles of European livestock sectors

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    There are increasing concerns about the ecological footprint of global animal production. Expanding livestock sectors worldwide contribute to expansion of agricultural land and associated deforestation, emissions of greenhouse gases (GHG), eutrophication of surface waters and nutrient imbalances. Farm based studies indicate that there are large differences among farms in animal productivity and environmental performance. Here, we report on regional variations in dairy, beef, pork, poultry and egg production, and related GHG emissions in the 27 Member States of the European Union (EU-27), based on 2003–2005 data. Analyses were made with the MITERRA-Europe model which calculates annual nutrient flows and GHG emissions from agriculture in the EU-27. Main input data were derived from CAPRI (i.e., crop areas, livestock distribution, feed inputs), GAINS (i.e., animal numbers, excretion factors, NH3 emission factors), FAO statistics (i.e., crop yields, fertilizer consumption, animal production) and IPCC (i.e., CH4, N2O, CO2 emission factors). Sources of GHG emissions included were enteric fermentation, manure management, direct and indirect N2O soil emissions, cultivation of organic soils, liming, fossil fuel use and fertilizer production. The dairy sector had the highest GHG emission in the EU-27, with annual emission of 195 Tg CO2-eq, followed by the beef sector with 192 Tg CO2-eq. Enteric fermentation was the main source of GHG emissions in the European livestock sector (36%) followed by N2O soil emissions (28%). On a per kg product basis, beef had by far the highest GHG emission with 22.6 kg CO2-eq/kg, milk had an emission of 1.3 kg CO2-eq/kg, pork 3.5 kg CO2-eq/kg, poultry 1.6 kg CO2-eq/kg, and eggs 1.7 kg CO2-eq/kg. However large variations in GHG emissions per unit product exist among EU countries, which are due to differences in animal production systems, feed types and nutrient use efficiencies. There are, however, substantial uncertainties in the base data and applied methodology such as assumptions surrounding allocation of feeds to livestock species. Our results provide insight into differences in GHG sources and emissions among animal production sectors for the various regions of Europe

    Biogeographical analysis of Late Silurian brachiopod faunas, chiefly from Asia and Australia

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    The roots of the wind of M82

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    4 figures. Submitted to PRL see paper for full list authorsSTAR's measurements of directed flow (v1v_1) around midrapidity for π±\pi^{\pm}, K±^{\pm}, KS0_S^0, pp and pˉ\bar{p} in Au + Au collisions at \sqrtsNN = 200 GeV are presented. A negative v1(y)v_1(y) slope is observed for most of produced particles (π±\pi^{\pm}, K±^{\pm}, KS0_{S}^{0} and pˉ\bar{p}). The proton v1(y)v_1(y) slope is found to be much closer to zero compared to antiprotons. A sizable difference is seen between v1v_1 of protons and antiprotons in 5-30% central collisions. The v1v_1 excitation function is presented. Comparisons to model calculations (RQMD, UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. Anti-flow alone cannot explain the centrality dependence of the difference between the v1(y)v_1(y) slopes of protons and antiprotons

    Chronic relapsing inflammatory optic neuropathy (CRION)

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    We describe the clinical characteristics and early natural history of a form of inflammatory optic neuropathy which is frequently bilateral and often painful, and is characterized by relapses and remissions. MRI scans of the brain are normal and those of the optic nerves often, but not always, show high signal abnormalities which enhance. The symptoms and signs respond well to corticosteroid treatment, although long-term immuno suppression is often necessary. The syndrome behaves in a way which is typical of the condition known as granulomatous optic neuropathy, but during a median follow-up of 8 (2-26) years in no case has evidence for systemic sarcoidosis been identified. We suggest that the disorder be named chronic relapsing inflammatory optic neuropathy (CRION
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