Search
Results
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Measurement of the running of the electromagnetic coupling at large momentum-transfer at LEP
(2005)Physics Letters BThe evolution of the electromagnetic coupling, α, in the momentum-transfer range 1800 GeV2 < -Q2 < 21600 GeV2 is studied with about 40 000 Bhabha-scattering events collected with the L3 detector at LEP at centre-of-mass energies √s = 189-209 GeV. The running of α is parametrised as: α(Q2) = α0/1 - C Δα(Q2), where α ≡ α(Q2 = 0) is the fine-structure constant and C = 1 corresponds to the evolution expected in QED. A fit to the differential ...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 -
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 -
Study of spin and decay-plane correlations of W bosons in the e(+) e(-)-> W+W- process at LEP
(2005)The European Physical Journal CData collected at LEP at centre-of-mass energies s√=189−209 GeV are used to study correlations of the spin of W bosons using e+e−→W+W−→\ensuremathℓνqq¯ events. Spin correlations are favoured by data, and found to agree with the Standard Model predictions. In addition, correlations between the W-boson decay planes are studied in e+e−→W+W−→\ensuremathℓνqq¯ and e+e−→W+W−→\ensuremathqq¯qq¯ events. Decay-plane correlations are measured to be ...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 -
Summary of the CMS potential for the Higgs boson discovery
(2005)The European Physical Journal CThis work summarizes the studies for the Higgs boson searches in CMS at the LHC collider. The main discovery channels are presented and the potential is given for the discovery of the SM Higgs boson and the Higgs bosons of the MSSM. The phenomenology, detector, trigger and reconstruction issues are briefly discussed.Journal Article -
Measurement of deeply virtual Compton scattering at HERA
(2005)The European Physical Journal CA measurement is presented of elastic deeply virtual Compton scattering γ∗p→\ensuremathγp made using e + p collision data corresponding to a luminosity of 46.5 pb-1, taken with the H1 detector at HERA. The cross section is measured as a function of the photon virtuality, Q 2, the invariant mass of the p system, W, and for the first time, differentially in the squared momentum transfer at the proton vertex, t, in the kinematic range ...Journal Article -
Measurement of charm and beauty photoproduction at HERA using D*mu correlations
(2005)Physics Letters B ~ Physics letters. BA measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D*± meson and a muon. The correlation between the D* meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm ...Journal Article