Multiplicity Fluctuations in One- and Two-Dimensional Angular Intervals Compared with Analytic QCD Calculations

TL;DR

This paper measures multiplicity fluctuations in specific angular regions around jets in electron-positron collisions and compares the results with analytical QCD predictions, finding qualitative agreement but notable quantitative differences.

Contribution

It provides experimental data on multiplicity fluctuations and tests analytical QCD calculations using Local Parton Hadron Duality at LEP energies.

Findings

Qualitative features match between data and theory.

Quantitative deviations observed from analytical predictions.

Supports the validity of Local Parton Hadron Duality concept.

Abstract

Multiplicity fluctuations in rings around the jet axis and in off-axis cones have been measured by the DELPHI collaboration in $e^+e^-$ annihilations into hadrons at LEP energies. The measurements are compared with analytical perturbative QCD calculations for the corresponding multiparton system, using the concept of Local Parton Hadron Duality. Some qualitative features are confirmed by the data but substantial quantitative deviations are observed.