Event Texture Search for Critical Fluctuations in Pb+Pb Collisions

Abstract

NA44 uses a 512 channel Si pad array covering $1.5<\eta <3.3$ to study charged hadron production in 158 A GeV Pb+Pb collisions at the CERN SPS. We apply a multiresolution analysis, based on a Discrete Wavelet Transformation, to probe the texture of particle distributions event-by-event, by simultaneous localization of features in space and scale. Scanning a broad range of multiplicities, we look for a possible critical behaviour in the power spectra of local density fluctuations. The data are compared with detailed simulations of detector response, using heavy ion event generators, and with a reference sample created via event mixing. An upper limit is set on the probability and magnitude of dynamical fluctuations.

4 pages, 4 figures, a talk at the Quark Matter 2001 parallel session III-B (Stony Brook, January 2001)