Detailed L3 measurements of Bose-Einstein correlations and a region of anti-correlations in hadronic Z^0 decays at LEP

TL;DR

This paper reports detailed measurements of Bose-Einstein correlations and anti-correlations in hadronic Z^0 decays at LEP, revealing a decrease in source size with increasing transverse mass and supporting the tau-model.

Contribution

It provides the first detailed analysis of Bose-Einstein correlations and anti-correlations in Z^0 decays, demonstrating the effectiveness of the tau-model in describing these phenomena.

Findings

Anti-correlations observed in the 0.5-1.6 GeV Q range with a minimum near 0.8 GeV

Absence of correlations above Q >= 1.6 GeV

Effective source size decreases with increasing transverse mass

Abstract

L3 preliminary data of two-particle Bose-Einstein correlations are reported for hadronic Z^0 decays in e+e- annihilation at LEP. The invariant relative momentum Q is identified as the eigenvariable of the measured correlation function. Significant anti-correlations are observed in the Bose-Einstein correlation function in a broad region of 0.5 - 1.6 GeV with a minimum at Q close to 0.8 GeV. Absence of Bose-Einstein correlations is demonstrated in the region above Q >= 1.6 GeV. The effective source size is found to decrease with increasing value of the transverse mass of the pair, similarly to hadron-hadron and heavy ion reactions. These feautes and our data are described well by the non-thermal tau-model, which is based on strong space-time momentum-correlations.