Benno List

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We present a study of J== meson production in collisions of 26:7 GeV electrons with 820 GeV protons, performed with the H1-detector at the HERA collider at DESY. The J== mesons are detected via their leptonic decays both to electrons and muons. Requiring exactly two particles in the detector, a cross section of (ep ! J==X) = (8:8 2:0 2:2) nb is determined(More)
Photoproduction of 2-jet events is studied with the H1 detector at HERA. Parton cross sections are extracted from the data by an unfolding method using leading order parton-jet correlations of a QCD generator. The gluon distribution in the photon is derived in the fractional momentum range 0:04 x 1 at the average factorization scale 75 GeV 2. H1(More)
Measurements of ep scattering with squared 4{momentum transfer Q 2 up to 35000 GeV 2 are compared with the expectation of the standard deep-inelastic model of lepton{nucleon scattering (DIS). For Q 2 > 15000 GeV 2 , N obs = 12 neutral current candidate events are observed where the expectation is N DIS = 4:71 0:76 events. In the same Q 2 range, N obs = 4(More)
Pleiotrophin is a heparin-binding growth factor involved in the differentiation and proliferation of neuronal tissue during embryogenesis, and also secreted by melanoma and breast carcinoma cells. Pleiotrophin exhibits mitogenic and angiogenic properties and has been shown to influence the vascular supply, expansion and metastasis of tumour cells. Our aim(More)
A measurement is presented, using data taken with the H1 detector at HERA, of the contribution of diiractive interactions to deep{inelastic electron{proton (ep) scattering in the kinematic range 8:5 < Q 2 < 50 GeV 2 , 2:410 ?4 < Bjorken{x < 0:0133, and 3:7 10 ?4 < x IP < 0:043. The diiractive contribution to the proton structure function F 2 (x; Q 2) is(More)
The photoproduction of beauty quarks in ep collisions has been measured using a data sample of 170 pb −1 collected with the H1 detector at HERA-II in the years 2006 and 2007. Events with two jets and a muon in the final state were investigated, and beauty events were identified using the muon's relative transverse momentum to a jet and its impact parameter.(More)
The total cross sections for the elastic electroproduction of % and J== mesons for Q 2 > 8 GeV 2 and hWi ' 90 GeV=c 2 are measured at HERA with the H1 detector. The measurements are for an integrated electron?proton luminosity of ' 3 pb ?1. The dependences of the total virtual photon?proton (p) cross sections on Q 2 , W and the momentum transfer squared to(More)
A thrust analysis of Large-Rapidity-Gap events in deep-inelastic ep collisions is presented , using data taken with the H1 detector at HERA in 1994. The average thrust of the nal states X, which emerge from the dissociation of virtual photons in the range 10 < Q 2 < 100 GeV 2 , grows with hadronic mass M X and implies a dominant 2-jet topology. Thrust is(More)
Events with no hadronic energy ow in a large interval of pseudo-rapidity in the proton direction are observed in photon-proton interactions at an average centre of mass energy < p s p > of 200 GeV. These events are interpreted as photon diirac-tive dissociation. Evidence for hard scattering in photon diiractive dissociation is demonstrated using inclusive(More)
During the last year many important results have been achieved in heavy flavour physics: New measurements of charm and beauty production have been performed at HERA and the Tevatron. A wealth of new spectroscopy data with several new, unexpected states in the charmonium and the Ds systems has been collected and b → dγ transitions have been established. The(More)