8 research outputs found

    Jets and energy flow in photon-proton collisions at HERA

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    Observation of hard processes in rapidity gap events in gamma-p interactions at Hera

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    Inclusive Photoproduction of Neutral Pions in the Photon Hemisphere at HERA

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    Observation of hard processes in rapidity gap events in gamma p interactions at HERA

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    Events with no hadronic energy flow in a large interval of pseudo-rapidity in the proton direction are observed in photon-proton interactions at an average centre of mass energy 〈sγp\sqrt {s_{ \gamma p}} 〉 of 200 GeV These events are interpreted as photon diffractive dissociation. Evidence for hard scattering in photon diffractive dissociation is demonstrated using inclusive single particle spectra, thrust as a function of transverse energy, and the observation of jet production. The data can be described by a Monte Carlo calculation including hard photon-pomeron scattering

    Determination of the strong coupling constant from jet rates in deep inelastic scattering

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    Jet rates in deep inelastic electron proton scattering are studied with the H1 detector at HERA for momentum transfers squared between 10 and 4000 GeV2^2 . It is shown that they can be quantitatively described by perturbative QCD in next to leading order making use of the parton densities of the proton and with the strong coupling constant αs\alpha_s as a free parameter. The measured value, αs(MZ2)=0.123±0.018\alpha_s ( M_Z^2 ) = 0.123 ± 0.018, is in agreement both with determinations from e+ee^+ e^− annihilation at LEP using the same observable and with the world average

    A measurement of the proton structure function f2(x.q2)f_2(x. q^2)

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    A measurement of the proton structure function F_{\!2}(x,Q^2) is reported for momentum transfer squared Q^2 between 4.5 GeV^2 and 1600 GeV^2 and for Bjorken x between 1.8\cdot10^{-4} and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that F_{\!2} increases significantly with decreasing x, confirming our previous measurement made with one tenth of the data available in this analysis. The Q^2 dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the "diffractive" contribution to F_{\!2}

    A measurement of the proton structure function f2(x.q2)f_2(x. q^2)

    No full text
    A measurement of the proton structure function F_{\!2}(x,Q^2) is reported for momentum transfer squared Q^2 between 4.5 GeV^2 and 1600 GeV^2 and for Bjorken x between 1.8\cdot10^{-4} and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that F_{\!2} increases significantly with decreasing x, confirming our previous measurement made with one tenth of the data available in this analysis. The Q^2 dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the "diffractive" contribution to F_{\!2}

    Beauty production in pp collisions at root s=2.76 TeV measured via semi-electronic decays

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    The ALICE Collaboration at the LHC reports measurement of the inclusive production cross section of electrons from semi-leptonic decays of beauty hadrons with rapidity |y| e) = 3.47 +/- 0.40(stat)(+1.12)(-1.33)(sys) +/- 0.07(norm) mu b, was extrapolated to full phase space using Fixed Order plus Next-to-Leading Log (FONLL) calculations to obtain the total b (b) over bar production cross section, sigma(b (b) over bar) = 130 +/- 15.1(stat)(+42.1)(-49.8)(sys)(+3.4)(-3.1)(extr) +/- 2.5(norm) +/- 4.4(BR) mu b. (C) 2014 The Authors. Published by Elsevier B.V
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