Antideuteron and deuteron production in midcentral Pb+Pb collisions at 158A GeV

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+p̅ )/(π++π−), and (K++K−)/(p+p̅ ) 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+p̅ )/(π++π−) ratio fluctuations. A description of the centrality and energy dependence of (K++K−)/(p+p̅ ) ratio fluctuations by a common scaling prescription is not possible since there is a sign change in the energy dependence.