Hadronic Expansion Dynamics in Central Pb+Pb Collisions at 158 GeV per Nucleon

TL;DR

This paper analyzes hadronic expansion in central Pb+Pb collisions at 158 GeV per nucleon, using two-particle correlations and spectra to extract source dynamics and resolve temperature-expansion velocity ambiguities.

Contribution

It introduces a novel Coulomb correction method and provides detailed dynamic characteristics of the hadronic source in heavy-ion collisions.

Findings

Determined source shape and expansion velocities.

Estimated freeze-out temperature and emission duration.

Resolved temperature and velocity ambiguities.

Abstract

Two-particle correlation functions of negative hadrons over wide phase space, and transverse mass spectra of negative hadrons and deuterons near mid-rapidity have been measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment at the CERN SPS. A novel Coulomb correction procedure for the negative two-particle correlations is employed making use of the measured oppositely charged particle correlation. Within an expanding source scenario these results are used to extract the dynamic characteristics of the hadronic source, resolving the ambiguities between the temperature and transverse expansion velocity of the source, that are unavoidable when single and two particle spectra are analysed separately. The source shape, the total duration of the source expansion, the duration of particle emission, the freeze-out temperature and the longitudinal and transverse expansion velocities are deduced.