Measurement of W-pair production in e+e- collisions at centre-of-mass energies from 183 to 209 GeV

Abstract

The W+W- production cross section is measured from a data sample corresponding to a total integrated luminosity of 683 pb -1, collected by the ALEPH experiment at LEP at centre-of-mass energies from 183 to 209 GeV. Individual cross sections for the different topologies arising from W decays into leptons or hadrons, as well as the total W-pair cross section are given at eight centre-of-mass energies. The results are found to be in agreement with recently developed Standard Model calculations at the one percent level. The hadronic branching fraction of the W boson is measured to be B(W → qq̄) = 67.13 ± 0.37 (stat.) ± 0.15 (syst.)%, from which the CKM matrix element |VCS| is determined to be 0.958 ± 0.017 (stat.) ± 0.008 (syst.). © Springer-Verlag / Società Italiana di Fisica 2004.