G. Abbiendi et al., W+W- production cross section and W branching fractions in e(+)e(-) collisions at 189 GeV, PHYS LETT B, 493(3-4), 2000, pp. 249-265
From a data sample of 183 pb(-1) recorded at a center-of-mass energy of roo
ts=189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are
selected. Assuming Standard Model W boson decay branching fractions, the W-
pair production cross section is measured to be sigma (WW) = 16.30 +/- 0.34
(stat.) +/- 0.18(syst.) pb. When combined with previous OPAL measurements,
the W boson branching fraction to hadrons is determined to be 68.32 +/- 0.6
1(stat.) +/- 0.28(syst.)% assuming lepton universality. These results are c
onsistent with Standard Model expectations. (C) 2000 Published by Elsevier
Science B.V.