Yano-Koonin-Podgoretskii parametrisation
of the Hanbury Brown-Twiss correlator
Y.-F. Wu 1 U. Heinz 1,2 - B. Tomásik 1 - U.A. Wiedemann 1
1 Institut für Theoretische Physik, Universität
Regensburg, D-93040 Regensburg, Germany
2 CERN/TH, CH-1211 Geneva 23, Switzerland
Received: 14 March 1997 / Revised version: 2 June 1997
Abstract
The Yano-Koonin-Podgoretskii (YKP) parametrisation of Hanbury Brown-Twiss
(HBT) two-particle correlation functions opens new strategies for
extracting the emission duration and testing the longitudinal
expansion in heavy-ion collisions. Based on the recently derived
model-independent expressions, we present a detailed parameter
study of the YKP parameters for a finite, hydrodynamically expanding
source model of heavy-ion collisions. For the class of models studied here,
we show that the three YKP radius parameters have an interpretation as
longitudinal extension, transverse extension and emission duration
of the source in the YKP frame. This frame is specified by
the fourth fit parameter, the Yano-Koonin velocity which describes
to a good approximation the velocity of the fluid element with highest
emissivity and allows to test for the longitudinal expansion of the
source. Deviations from this interpretation of the YKP parameters are
discussed quantitatively.
Copyright Springer-Verlag
