Measurement and interpretation of the W-pair cross-section in e(+)e(-) interactions at 161 GeV

In 1996 LEP ran at a centre-of-mass energy of 161 GeV, just above the threshold of W-pair production. DELPHI accumulated data corresponding to an integrated luminosity of 9.93 pb(-1), and observed 29 events that are considered as candidates for W-pair production. From these, a cross-section for the doubly resonant e(+)e(-) --> WW process of 3.67(-0.85)(+0.97)+/-0.19 pb has been measured. Within the Standard Model, this cross-section corresponds to a mass of the W-boson of 80.40+/-0.44(stat.)+/-0.09(syst.)+/-0.03(LEP) GeV/c(2). Alternatively, if mw is held fixed at its current value determined by other experiments, the observed cross-section is used to obtain limits on trilinear WWV(V = gamma,Z) couplings. (C) 1997 Elsevier Science B.V.