Six-jet decay of off-shell WW pairs at e+e− colliders

Six-jet events via WW pairs, e+e− → W+W− → q1q1q2q2gg are studied at tree level using helicity amplitudes. This is the dominant production mechanism for six-jet final states at LEP II energy. ISR effects are taken into account. Total production rates as a function of ycut are given. The relevance of these processes for the issue of colour reconnection is discussed. The cross section for five-jet production via WW pairs at LEP II is also presented.