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Inclusive jet production in two-photon collisions at LEP
(2011)Physics Letters BInclusive jet production, e+e- → e +e- jet X, is studied using 560 pb-1 of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 209 GeV. The inclusive differential cross section is measured using a kt jet algorithm as a function of the jet transverse momentum, pt, in the range 3 < pt < 50 GeV for a pseudorapidity, η, in the range -1 <η <1. This cross section is well represented by a power law. For high pt, ...Journal Article -
Test of the τ-model of Bose–Einstein correlations and reconstruction of the source function in hadronic Z-boson decay at LEP
(2011)The European Physical Journal CBose–Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a Lévy stable distribution in conjunction with a model where a particle’s momentum is correlated with its space–time point of production, the τ-model. Using this description and the measured rapidity and transverse momentum distributions, the space–time evolution ...Journal Article -
Study of hadronic event shape in flavour tagged events in e+e- annihilation at ⟨√s⟩ = 197 GeV
(2008)PMC Physics. AResults are presented from a study of the structure of hadronic events in high-energy e+e- interactions detected by the L3 detector at LEP. Various event shape distributions and their moments are measured at several energy points at and above the Z-boson mass. The event flavour is tagged by using the decay characteristics of b-hadrons. Measurements of distributions of event shape variables for all hadronic events, for light (u, d, s, c) ...Journal Article -
Study of inclusive strange-baryon production and search for pentaquarks in two-photon collisions at LEP
(2007)The European Physical Journal CMeasurements of inclusive production of the Λ, Ξ- and Ξ*(1530) baryons in two-photon collisions with the L3 detector at LEP are presented. The inclusive differential cross sections for Λ and Ξ- are measured as a function of the baryon transverse momentum, pt, and pseudo-rapidity, η. The mean number of Λ, Ξ- and Ξ*(1530) baryons per hadronic two-photon event is determined in the kinematic range 0.4 GeV<pt<2.5 GeV, |η|<1.2. Overall agreement ...Journal Article -
Search for neutral MSSM Higgs bosons at LEP
(2006)The European Physical Journal CThe four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of ...Journal Article -
Measurement of hadron and lepton-pair production in e+e- collisions at root s=192-208 GeV at LEP
(2006)The European Physical Journal CHadron production and lepton-pair production in e+e- collisions are studied with data collected with the L3 detector at LEP at centre-of-mass energies s√=192−208GeV. Using a total integrated luminosity of 453 pb-1, 36057 hadronic events and 12863 lepton-pair events are selected. The cross sections for hadron production and lepton-pair production are measured for the full sample and for events where no high-energy initial-state-radiation ...Journal Article -
Measurement of the mass and the width of the W boson at LEP
(2006)The European Physical Journal CThe mass and the total decay width of the W boson are measured with the L3 detector at the LEP e+e– collider using W-boson pairs produced in 0.7 fb–1 of data collected at centre-of-mass energies between 161 and 209 GeV. Combining semi-leptonic and fully-hadronic final states, the mass and the width of the W boson are determined to be mW=80.270±0.046±0.031GeVandΓW=2.18±0.11±0.09GeV where the first uncertainty is statistical and the ...Journal Article -
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 -
Neutral-current four-fermion production in e+e- interactions at LEP
(2005)Physics Letters BNeutral-current four-fermion production, e+e -→ff̄f′f̄′, is studied in 0.7 fb -1 of data collected with the L3 detector at LEP at centre-of-mass energies s=183-209 GeV. Four final states are considered: qq̄νν̄ , qq̄ℓ+ℓ-, ℓ+ℓ-ℓ′+ℓ′- and ℓ+ℓ-νν̄, where ℓ denotes either an electron or a muon. Their cross sections are measured and found to agree with the Standard Model predictions. In addition, the e+e-→Zγ *→ff̄f′f̄′ process is studied and ...Journal Article -
Measurement of the cross section of W-boson pair production at LEP
(2004)Physics Letters BThe cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4 pb−1, collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4% and agrees with the Standard Model expectation. Assuming charged-lepton ...Journal Article