Local Multiplicity Fluctuations in Z decay

TL;DR

This paper investigates local multiplicity fluctuations in Z boson decays using L3 data, revealing multifractal structures within jets and comparing experimental results with JETSET 7.4 PS simulations.

Contribution

It introduces the use of bunching parameters to study multiplicity fluctuations and compares these with factorial moments, providing new insights into jet structure in Z decays.

Findings

Multifractal structures observed inside jets.

JETSET 7.4 PS models fluctuations in azimuthal angle well.

JETSET overestimates fluctuations in rapidity and four-momentum difference.

Abstract

Local multiplicity fluctuations of hadrons produced in the decay of $Z^0$ were studied on the basis of L3 data. In addition to the normalized-factorial-moment method, the fluctuations were studied for the first time by the use of bunching parameters. A strong multifractal structure was observed inside jets. JETSET 7.4 PS describes the fluctuations in the azimuthal angle defined with respect to the beam axis reasonably well. For the fluctuations in rapidity, defined with respect to the thrust axis and in the four-momentum-difference variable, JETSET 7.4 PS overestimates the fluctuations.