Fluctuations of particle ratios as a freeze-out probe
Abstract
We explain how event-by-event fluctuations of particle ratios can constrain and falsify the statistical model of particle production in heavy-ion collisions, using K/π 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/π 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 what happens in case of 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*/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
- Publication:
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Journal of Physics G Nuclear Physics
- Pub Date:
- April 2008
- DOI:
- 10.1088/0954-3899/35/4/044009
- arXiv:
- arXiv:0710.0380
- Bibcode:
- 2008JPhG...35d4009T
- Keywords:
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- Nuclear Theory
- E-Print:
- Proceedings for talk given at Strangeness 2007, Levoca, Slovakia