On event-by-event fluctuations in nuclear collisions
Marek Gazdzicki1 - Andrei Leonidov2 - Gunther Roland1
1 Institut für Kernphysik, Universität Frankfurt,
August-Euler Str. 6, D-60486 Frankfurt/M, Germany
2 P.N. Lebedev Physics Institute, 117924 Leninsky pr. 53, Moscow, Russia
Received: 23 January 1998 / Published online: 30 July 1998
We demonstrate that a new type of analysis in heavy-ion collisions, based on an event-by-event analysis of the transverse momentum distribution, allows us to obtain information on secondary interactions and collective behaviour that is not available from the inclusive spectra. Using a random walk model as a simple phenomenological description of initial state scattering in collisions with heavy nuclei, we show that the event-by-event measurement allows a quantitative determination of this effect, well within the resolution achievable with the new generation of large acceptance hadron spectrometers. The preliminary data of the NA49 collaboration on transverse momentum fluctuations indicate qualitatively different behaviour than that obtained within the random walk model. The results are discussed in relation to the thermodynamic and hydrodynamic description of nuclear collisions.