Charged particle multiplicity and momenta in $e^{+}e^{-} \to W$-pair decays at 189 GeV

The charged particle multiplicity of W-pair decays is measured with the ALEPH detector at LEP at a cms energy of 189GeV. This is motivated by the study of possible colour reconnection effects in W-pairs where both decay hadronically. The average charged multiplicity of WW>qqqq is compared with predictions of fragmentation models tuned to measurements performed at the Z peak and with measured multiplicities in WW>qqlv events. It is compatible, both with models without implementation of colour reconnection, and with the models including colour reconnection that are studied here.