Bose-Einstein Correlations and the Tau-Model

TL;DR

This paper analyzes Bose-Einstein correlations in hadronic Z decays, demonstrating the tau model's effectiveness and identifying a longitudinal elongation in the emission region that challenges the model.

Contribution

It introduces a modified tau model to account for observed elongation in the emission region in Bose-Einstein correlation data.

Findings

Good fit with Lévy stable distribution and tau model

Observation of elongation in emission region in Longitudinal Center of Mass frame

Modified tau model partially accounts for elongation

Abstract

Bose-Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a L\'evy stable distribution in conjunction with a model where a particle's momentum is highly correlated with its space-time point of production, the tau model. However, a small but significant elongation of the particle emission region is observed in the Longitudinal Center of Mass frame, which is not accommodated in the tau model. This is investigated using an ad hoc modification of the tau model.