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Search for the QCD critical point in nuclear collisions at the CERN SPS
- Publication Year :
- 2009
-
Abstract
- Pion production in nuclear collisions at the SPS is investigated with the aim to search, in a restricted domain of the phase diagram, for power-laws in the behavior of correlations which are compatible with critical QCD. We have analyzed interactions of nuclei of different size (p+p, C+C, Si+Si, Pb+Pb) at 158$A$ GeV adopting, as appropriate observables, scaled factorial moments in a search for intermittent fluctuations in transverse dimensions. The analysis is performed for $\pi^+\pi^-$ pairs with invariant mass very close to the two-pion threshold. In this sector one may capture critical fluctuations of the sigma component in a hadronic medium, even if the $\sigma$-meson has no well defined vacuum state. It turns out that for the Pb+Pb system the proposed analysis technique cannot be applied without entering the invariant mass region with strong Coulomb correlations. As a result the treatment becomes inconclusive in this case. Our results for the other systems indicate the presence of power-law fluctuations in the freeze-out state of Si+Si approaching in size the prediction of critical QCD.<br />Comment: 31 pages, 11 figures
- Subjects :
- High Energy Physics - Experiment (hep-ex)
High Energy Physics - Phenomenology
High Energy Physics - Phenomenology (hep-ph)
Nuclear Theory
FOS: Physical sciences
Nuclear Physics - Experiment
High Energy Physics::Experiment
Nuclear Experiment (nucl-ex)
Nuclear Experiment
High Energy Physics - Experiment
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....c0e7d020189e631334c547f2d4a655ec