New measurements by the NA49 experiment of the centrality dependence of event-by-event fluctuations of the particle yield ratios (K++K -)/(π++π-), (p+p̄) /(π++π-), and (K++K-)/ (p+p̄) are presented for Pb+Pb collisions at 158A GeV. The absolute values of the dynamical fluctuations of these ratios, quantified by the measure σdyn, increase by about a factor of two from central to semiperipheral collisions. Multiplicity scaling scenarios are tested and found to apply for both the centrality and the previously published energy dependence of the (K++K-)/(π++π-) and (p+p̄)/(π++π-) ratio fluctuations. A description of the centrality and energy dependence of (K++K -)/(p+p̄) ratio fluctuations by a common scaling prescription is not possible since there is a sign change in the energy dependence.
ASJC Scopus subject areas
- Nuclear and High Energy Physics