Central Pb+Pb collisions at 158 A GeV/c studied by interferometry
The WA98 Collaboration
M.M. Aggarwal1 - et al.
1 University of Panjab, Chandigarh 160014, India
Received: 3 February 2000 / Published online: 18 May 2000 - © Springer-Verlag 2000
Two-particle correlations have been measured for identified from central 158 A GeV Pb+Pb collisions and fitted radii of about 7 fm in all dimensions have been obtained. A multi-dimensional study of the radii as a function of kT is presented, including a full correction for the resolution effects of the apparatus. The cross term R2out-long of the standard fit in the Longitudinally CoMoving System (LCMS) and the vL parameter of the generalised Yano-Koonin fit are compatible with 0, suggesting that the source undergoes a boost invariant expansion.
The shapes of the correlation functions in Qinv and have been analyzed in detail. They are not Gaussian but better represented by exponentials. As a consequence, fitting Gaussians to these correlation functions may produce different radii depending on the acceptance of the experimental setup used for the measurement.
Copyright Società Italiana di Fisica, Springer-Verlag 2000