Factorial and cumulant moments in e+e− → hadrons at the Z0 resonance

We present the first experimental study of the ratio of cumulant to factorial moments of the charged-particle multiplicity distribution in high-energy particle interactions, using hadronic Z0 decays collected by the SLD experiment at SLAC. We find that this ratio, as a function of the moment-rank q, decreases sharply to a negative minimum at q = 5, which is followed by quasi-oscillations. These features are insensitive to experimental systematic effects and are in qualitative agreement with expectations from next-to-next-to-leading-order perturbative QCD.