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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 -
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 -
Measurement of event shape variables in deep-inelastic scattering at HERA
(2006)The European Physical Journal CDeep-inelastic ep scattering data taken with the H1 detector at HERA and corresponding to an integrated luminosity of 106 pb-1 are used to study the differential distributions of event shape variables. These include thrust, jet broadening, jet mass and the C-parameter. The four-momentum transfer Q is taken to be the relevant energy scale and ranges between 14 GeV and 200 GeV. The event shape distributions are compared with perturbative ...Journal Article -
Measurement of F2c[`(c)]F2ccˉ and F2b[`(b)]F2bbˉ at low Q2 and x * using the H1 vertex detector at HERA
(2006)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 12 ≤ Q2 ≤ 60 GeV2 and of the Bjorken scaling variable 0.0002 x ≤ 0.005. The fractions of events containing charm and beauty quarks 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. Values for the structure ...Journal Article -
Forward jet production in deep inelastic scattering at HERA
(2006)The European Physical Journal CThe production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable (x Bj ) and as triple differential cross sections d 3σ/dx Bj dQ 2 dp2t,jet, where Q 2 is the four momentum transfer squared and p2t,jet is the squared transverse momentum of the forward jet. Also cross sections for events with a ...Journal Article