Bose-Einstein Correlations in Multihadron Events at LEP

TL;DR

This paper investigates Bose-Einstein correlations among identical particles produced in electron-positron collisions at LEP, revealing insights into source size, shape, and dynamics, including evidence for an expanding particle emission source.

Contribution

It provides a comprehensive analysis of Bose-Einstein correlations across various particle types and kinematic conditions, highlighting the non-spherical, expanding nature of the emission source.

Findings

Source radius depends on particle mass.

The emission source is not spherically symmetric.

Data supports an expanding emission source.

Abstract

Bose-Einstein correlations in pairs of identical particles were analyzed in e+ e- multihadron annihilations at ~91.2 GeV at LEP. The first studies involved identical charged pions and the emitting source size was determined. Then the study of charged kaons suggested that the radius depends on the mass of the emitted particles. Subsequenty the dependence of the source radius on the event multiplicity was analyzed. The study of the correlations in neutral pions and neutral kaons extended these concepts to neutral particles. The shape of the source was analyzed in 3 dimensions and was found not to be spherically symmetric. In recent studies at LEP the correlations were analyzed in intervals of the average pair transverse momentum and of the pair rapidity to study the correlations between the pion production points and their momenta (position-momentum correlations). The latest e+ e- data are consistent with an expanding source.