System size dependence of particle-ratio fluctuations in Pb+Pb collisions at 158A GeV

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