Measurement of the production of the four-fermion final states mediated byneutral current processes

We report on the observation of the four-fermion final states originating from the neutral current processes, in the data sample collected by the DELPHI detector at the centre-of-mass energy of 188.6 GeV. The preliminary measurements of the differential cross-sections for the production of μ+μ−qq, e+e−qq l+l−l+l− and ννqq final states outside the on-shell ZZ region have been compared with the Standard Model expectations.