What can we learn from fluctuations of particle ratios?

Abstract

We explain how fluctuations of ratios can constrain and falsify the statistical model of particle production in heavy ion collisions, using $K/\pi$ fluctuations as an example. We define an observable capable of determining which statistical model, if any, governs freeze-out in ultrarelativistic heavy ion collisions. We calculate this observable for $K/\pi$ fluctuations, and show that it should be the same for RHIC and LHC energies, as well as independent of centrality, if the Grand-Canonical statistical model is an appropriate description and chemical equilibrium applies. We describe variations of this scaling for deviations from this scenario, such as light quark chemical non-equilibrium, strange quark over-saturation and local conservation (canonical ensemble) for strange quarks. We also introduce a similar observable capable, together with the published $K^{\ast }/K$ measurement, of ascertaining if an interacting hadron gas phase governs the system between thermal and chemical freeze-out, and of ascertaining its duration and impact on hadronic chemistry.

Talk, Critical Point and the Onset of Deconfinement 2007

References in corpus (5)

• Core-Corona Separation in Ultra-Relativistic Heavy Ion Collisions
• Hydrodynamic description of ultrarelativistic heavy-ion collisions
• Status of Chemical Freeze-Out
• Resonances and fluctuations of strange particle in 200 GeV Au-Au collisions
• Is Chemical Equilibrium achieved in Collisions of Small Systems at the SPS?