Studies of Hadronic Event Structure in e+e- Annihilation from 30 GeV to 209 GeV with the L3 Detector

TL;DR

This paper presents measurements of quantum chromodynamics (QCD) in electron-positron collisions at energies from 30 GeV to 209 GeV, focusing on the strong coupling constant and soft gluon effects using the L3 detector at LEP.

Contribution

It provides new measurements of mbda_s and soft gluon coherence effects across a wide energy range, testing QCD predictions with high precision.

Findings

Measured mbda_s at multiple energies confirming QCD running

Observed soft gluon coherence effects in particle multiplicity

Validated QCD predictions for event shape observables

Abstract

In this Report, QCD results obtained from a study of hadronic event structure in high energy e^+e^- interactions with the L3 detector are presented. The operation of the LEP collider at many different collision energies from 91 GeV to 209 GeV offers a unique opportunity to test QCD by measuring the energy dependence of different observables. The main results concern the measurement of the strong coupling constant, \alpha_s, from hadronic event shapes and the study of effects of soft gluon coherence through charged particle multiplicity and momentum distributions.