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Search for single top quark production in ep collisions at HERA
(2004)The European Physical Journal CA search for single top quark production is performed in e±p collisions at HERA. The search exploits data corresponding to an integrated luminosity of 118.3 pb-1. A model for the anomalous production of top quarks in a flavour changing neutral current process involving a tuγ coupling is investigated. Decays of top quarks into a b quark and a W boson are considered in the leptonic and the hadronic decay channels of the W. Both a cut-based ...Journal Article -
Measurement of beauty production at HERA using events with muons and jets
(2005)The European Physical Journal CA measurement of the beauty production cross section in ep collisions at a centre-of-mass energy of 319 GeV is presented. The data were collected with the H1 detector at the HERA collider in the years 1999-2000. Events are selected by requiring the presence of jets and muons in the final state. Both the long lifetime and the large mass of b-flavoured hadrons are exploited to identify events containing beauty quarks. Differential cross ...Journal Article -
Inclusive dijet production at low Bjorken-x in deep inelastic scattering
(2004)The European Physical Journal CDijet production in deep inelastic ep scattering is investigated in the region of low values of the Bjorken-variable x (10-4 < x < 10-2) and low photon virtualities Q 2 (5 < Q 2 < 100 GeV2). The measured dijet cross sections are compared with perturbative QCD calculations in next-to-leading order. For most dijet variables studied, these calculations can provide a reasonable description of the data over the full phase space region covered, ...Journal Article -
Measurement of prompt photon cross sections in photoproduction at HERA
(2005)The European Physical Journal CResults are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the γp center of mass energy range 142 < W < 266 GeV. The cross sections are measured for the transverse momentum range of the photons 5<EγT<10 GeV and for associated jets with E T jet > 4.5 GeV. They are measured differentially as a function of EγT,EjetT, the pseudorapidities ηγ and ηjet and estimators of the momentum fractions ...Journal Article -
Measurement of F-2(c(c)over-bar) and F-2(b(b)over-bar) at high Q(2) using the H1 vertex detector at HERA
(2005)The European Physical Journal CMeasurements are presented of inclusive charm and beauty cross sections in e + p collisions at HERA for values of photon virtuality Q 2 > 150 GeV2 and of inelasticity 0.1 < y < 0.7. The charm and beauty fractions are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. The data are divided into four regions in Q 2 and Bjorken x, and values ...Journal Article -
Measurement of dijet cross sections in ep interactions with a leading neutron at HERA
(2005)The European Physical Journal CMeasurements are reported of the production of dijet events with a leading neutron in ep interactions at HERA. Differential cross sections for photoproduction and deep inelastic scattering are presented as a function of several kinematic variables. Leading order QCD simulation programs are compared with the measurements. Models in which the real or virtual photon interacts with a parton of an exchanged pion are able to describe the data. ...Journal Article -
Inclusive production of D+, D0, D+ s and D∗+ mesons in deep inelastic scattering at HERA
(2005)The European Physical Journal CInclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality 2 < Q 2 < 100 Gev2, inelasticity 0.05 < y < 0.7, D meson transverse momenta pt(D)≥2.5 Gev and pseudorapidity |η(D)|≤1.5. The identification of the D-meson decays and the reduction of the combinatorial ...Journal Article -
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 -
Elastic J/ψ production at HERA
(2006)The European Physical Journal CCross sections for elastic production of J/ψ mesons in photoproduction and electroproduction are measured in electron proton collisions at HERA using an integrated luminosity of 55 pb-1. Results are presented for photon virtualities Q2 up to 80 GeV2. The dependence on the photon-proton centre of mass energy Wγp is analysed in the range 40≤Wγp≤305 GeV in photoproduction and 40≤Wγp≤160 GeV in electroproduction. The Wγp dependences of the ...Journal Article