Showing papers by "G. Mirabelli published in 1992"
TL;DR: In this paper, the number of light neutrino species is found to be Nv=3.30% CL with the constraints of the standard electroweak model, which rules out the possibility of a fourth type of LN at 98% CL.
234 citations
TL;DR: In this article, the structure of hadronic events from Z ≥ 0 decay is studied by measuring event shape variables, factorial moments, and the energy flow distribution, after correction for detector effects and initial and final state radiation, compared with the predictions of different QCD Monte Carlo programs with optimized parameter values.
Abstract: The structure of hadronic events fromZ
0 decay is studied by measuring event shape variables, factorial moments, and the energy flow distribution. The distributions, after correction for detector effects and initial and final state radiation, are compared with the predictions of different QCD Monte Carlo programs with optimized parameter values. These Monte Carlo programs use either the second order matrix element or the parton shower evolution for the perturbative QCD calculations and use the string, the cluster, or the independent fragmentation model for hadronization. Both parton shower andO(α
2
s
matrix element based models with string fragmentation describe the data well. The predictions of the model based on parton shower and cluster fragmentation are also in good agreement with the data. The model with independent fragmentation gives a poor description of the energy flow distribution. The predicted energy evolutions for the mean values of thrust, sphericity, aplanarity, and charge multiplicity are compared with the data measured at different center-of-mass energies. The parton shower based models with string or cluster fragmentation are found to describe the energy dependences well while the model based on theO(α
2
s
calculation fails to reproduce the energy dependences of these mean values.
66 citations
TL;DR: In this article, a study of the global event shape variables thrust and heavy jet mass, of energy-energy correlations and of jet multiplicities based on 250 000 hadronic Z 0 decays is presented.
64 citations
TL;DR: In this paper, the total and differential cross sections of the reaction e+e− → γγ(γ) at center-of-mass energies around 91 GeV, with an integrated luminosity of 14.2 pb−1.
23 citations
TL;DR: In this paper, the fraction of the J mesons from b-hadron decay was calculated and a branching ratio of Br(b → J + X) = (1.3±0.2(stat.)± 0.3 (sys.)) × 10−3.
23 citations
TL;DR: In this paper, the forward-backward asymmetry of the Z 0.2336±0.0029 hadronic decays of the single lepton and dilepton p and pT spectra was measured using hadronic events containing muons or electrons.
23 citations
TL;DR: In this article, a sample of e+e− annihilation events collected at the Z resonance corresponding to an integrated luminosity of 11.2 pb−1 was used to search for γX final states where X represents stable, weakly interacting particles and the energy of the photon is greater than 1 2 E beam.
20 citations
TL;DR: In this paper, the authors present a study of the inclusive η production based on 300 000 hadronic Z 0 decays and find that the measured inclusive momentum distribution can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation.
19 citations