0000000000102869
AUTHOR
J Y Nief
Analysis of transverse momentum correlations in hadronic Z decays
In a recent paper, evidence was presented for a significant, positive correlation between the total transverse momenta of particles on opposite hemispheres of hadronic events. A new, model independent analysis of the data has been made. Two components can be distinguished in the correlation, and quantitative estimates of each are given. The results form a significant test of Monte Carlo models and some of the physics behind them. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Search for invisible Higgs boson decays in e+e- collisions at centre-of-mass energies up to 184 GeV
In a data sample of 78.3 pb(-1) collected in 1996 and 1997 by the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, invisible decays of a Higgs boson have been searched for in the reaction e(+)e(-) --> hZ, where the Z can decay into e(+)e(-), mu(+) mu(-) or . No evidence for a signal is found and limits on the production cross section are derived as a function of the Higgs boson mass. These results are combined with those obtained in an update of the analyses of the ALEPH data taken at LEP 1. For a production cross section equal to that of the minimal standard model Higgs boson, masses below 80 GeV/c(2) are excluded at 95% C.L. (C) 1999 Elsevier Science B.V. All rights reserved.