5,149 research outputs found

    NA49 Energy Scan Results for Central Lead-Lead Collisions at the CERN SPS

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    The energy dependence of hadron production in central Pb-Pb collisions at SPS energies is presented and compared with data at lower and higher energies and with results from p-p interactions. It is observed that there is little change in transverse activity in the SPS energy range, that there is a steepening rate of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum which is weaker in Ksi/pi and absent in Omega/pi.Comment: To appear in the proceedings of the 39th Rencontres de Moriond on QCD and High-Energy Hadronic Interactions, La Thuile, March 28 - April 4, 200

    Future measurements of alpha_s and xg from scaling violations at HERA

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    Results are presented of a study of the experimental and theoretical accuracy one may achieve at HERA in measuring the strong coupling constant alpha_s and the gluon distribution from scaling violations of F2 structure functions.Comment: 7 pages, 2 figures. Latex source file and 2 separate .ps files. Talk presented at the DIS97 workshop, Chicago, April 14-18 199

    Error Estimates on Parton Density Distributions

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    Error estimates on parton density distributions are presently based on the traditional method of least squares minimisation and linear error propagation in global QCD fits. We review the underlying assumptions and the various mathematical representations of the method and address some technical issues encountered in such a global analysis. Parton distribution sets which contain error information are described.Comment: Latex, 12 pages, 5 figures. Needs iopart.cls and iopart12.clo. Presented at New Trends in HERA Physics 2001, Ringberg Castle, Tegernsee, Germany, June 17-22, 200

    Inclusive Deep Inelastic Scattering at HERA and related phenomenology

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    Recent measurements of inclusive deep inelastic scattering differential cross-section in the range 1.5 \gev2\le Q^2\le 30000 \gev2 and 5\cdot 10^{-6}\le x\le 0.65 are presented. Phenomenological analyses performed from these measurements are also described.Comment: 14 page

    Heavy Quark Production in the ACOT Scheme Beyond NLO

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    We analyze the properties of the ACOT scheme for heavy quark production and make use of the MS-Bar massless results at NNLO and N3LO for the structure functions F2 and FL in neutral current deep-inelastic scattering to estimate the higher order corrections. The dominant heavy quark mass effects at higher orders can be taken into account using the massless Wilson coefficients together with an appropriate slow-rescaling prescription implementing the phase space constraints. Combining the exact ACOT scheme at NLO with these expressions should provide a good approximation to the full calculation in the ACOT scheme at NNLO and N3LO.Comment: 4 pages, 2 figures. Presented at DIS12, March 2012, Bonn, German
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