Particle yield fluctuations and chemical nonequilibrium in Au-Au collisions at sNN=200 GeV

We study charge fluctuations within the statistical hadronization model. Considering both the particle yield ratios and the charge fluctuations we show that it is possible to differentiate between chemical equilibrium and non-equilibrium freeze-out conditions. As an example of the procedure we show quantitatively how the relative yield ratio Λ/K- together with the normalized net charge fluctuation v(Q)= (ΔQ)2/Nch constrain the chemical conditions at freeze-out. We also discuss the influence of the limited detector acceptance on fluctuation measurements, and show how this can be accounted for within a quantitative analysis.