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Study of charm fragmentation into D (* +/-) mesons in deep-inelastic scattering at HERA
(2009)The European Physical Journal CThe process of charm quark fragmentation is studied using D * ± meson production in deep-inelastic scattering as measured by the H1 detector at HERA. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the ...Journal Article -
Correlations between polarisation states of W particles in the reaction e-e+→W-W+ at LEP2 energies 189-209 GeV
(2009)The European Physical Journal CIn a study of the reaction e − e +→W − W + with the DELPHI detector, the probabilities of the two W particles occurring in the joint polarisation states transverse–transverse (TT), longitudinal–transverse plus transverse–longitudinal (LT) and longitudinal–longitudinal (LL) have been determined using the final states WW→lνqq¯ (l=e,μ). The two-particle joint polarisation probabilities, i.e. the spin density matrix elements ρ TT , ρ LT , ρ ...Journal Article -
Inclusive single-particle production in two-photon collisions at LEP II with the DELPHI detector
(2009)Physics Letters BA study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle pT distribution and the differential charged hadrons d σ / d pT cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results.Journal Article -
Deeply virtual Compton scattering and its beam charge asymmetry in e±p collisions at HERA
(2009)Physics Letters BA measurement of elastic deeply virtual Compton scattering γ * p → γ p using e + p and e - p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb -1, almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q 2 of the exchanged photon and the centre-of-mass energy W of the γ * p system in the ...Journal Article -
A measurement of coherent neutral pion production in neutrino neutral current interactions in the NOMAD experiment
(2009)Physics Letters BWe present a study of exclusive neutral pion production in neutrino-nucleus Neutral Current interactions using data from the NOMAD experiment at the CERN SPS. The data correspond to 1.44 × 10 6 muon-neutrino Charged Current interactions in the energy range 2.5 ≤ E ν ≤ 300 GeV. Neutrino events with only one visible π 0 in the final state are expected to result from two Neutral Current processes: coherent π 0 production, ν + A → ν + A + π ...Journal Article -
A precision measurement of the inclusive ep scattering cross section at HERA
(2009)The European Physical Journal CA measurement of the inclusive deep inelastic neutral current e + p scattering cross section is reported in the region of four-momentum transfer squared, 12 GeV2≤Q 2≤150 GeV2, and Bjorken x, 2×10−4≤x≤0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E e =27.6 GeV and E p =920 GeV, respectively. The data are combined with previously published data, taken at ...Journal Article -
Measurement of diffractive scattering of photons with large momentum transfer at HERA
(2009)Physics Letters BJournal Article -
A general search for new phenomena at HERA
(2009)Physics Letters BA model-independent search for deviations from the Standard Model prediction is performed using the full e±p data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for ...Journal Article -
Observation of the hadronic final state charge asymmetry in high Q2 deep-inelastic scattering at HERA
(2009)Physics Letters BA first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in deep-inelastic ep neutral current scattering at HERA. The measurement is performed in the range of negative squared four momentum transfer 100 < Q 2 < 8000 GeV 2. The difference between the event normalised distributions of the scaled momentum, x p, for positively and negatively charged particles, measured in the current region ...Journal Article -
Inclusive photoproduction of ρ0, K*0 and ϕ mesons at HERA
(2009)Physics Letters BInclusive non-diffractive photoproduction of ρ (770) 0, K * (892) 0 and φ{symbol} (1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average γp centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5 < p T < 7 GeV and the rapidity range | y lab | < 1. Differential cross sections are presented as a function of transverse momentum and rapidity, and are compared ...Journal Article