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Results on J== production in ep interactions in the H1 experiment at HERA are presented. The J== mesons are produced by almost real photons (Q 2 0) and detected via their leptonic decays. The data have been taken in 1994 and correspond to an integrated luminosity of 2:7 pb ?1. The p cross section for elastic J== production is observed to increase strongly(More)
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)
Measurements are presented of differential dijet cross sections in diffractive photoproduc-tion (É ¾ ¼¼½ GeV ¾) and deep-inelastic scattering processes (DIS, É ¾ ¼ GeV ¾). The event topology is given by Ô , in which the system , containing at least two jets, is separated from a leading low-mass proton remnant system by a large rapidity gap. The dijet cross(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)
A leading order determination of the gluon density in the proton has been performed in the fractional momentum range 1:9 10 ?3 < x g=p < 0:18 by measuring multi-jet events from boson-gluon fusion in deep-inelastic scattering with the H1 detector at the electron-proton collider HERA. This direct determination of the gluon density was performed in a kinematic(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)
Jet event rates in deep inelastic ep scattering at HERA are investigated applying the modiied JADE jet algorithm. The analysis uses data taken with the H1 detector in 1994 and 1995. The data are corrected for detector and hadronization eeects and then compared with perturbative QCD predictions using next-to-leading order calculations. The strong coupling(More)