Factorial and Cumulant Moments in $e^{+}e^{-}\to$ Hadrons at the Z$^0$ Resonance

TL;DR

This paper reports the first experimental measurement of the ratio of cumulant to factorial moments in charged-particle multiplicity distributions from Z$^0$ decays, revealing a characteristic pattern consistent with advanced QCD predictions.

Contribution

It provides the first experimental analysis of cumulant to factorial moment ratios in Z$^0$ hadronic decays, confirming theoretical QCD expectations.

Findings

Ratio decreases sharply to a negative minimum at q=5

Quasi-oscillations observed in the ratio as a function of q

Results are insensitive to systematic effects and match QCD predictions

Abstract

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 Z$^0$ 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.