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ID: 544659.0, MPI für Physik / MPI für Physik
Search for the QCD critical point in nuclear collisions at 158 A GeV at the CERN Super Proton Synchrotron (SPS)
Authors:
Date of Publication (YYYY-MM-DD):2010
Title of Journal:Physical Review C
Journal Abbrev.:Phys.Rev.C
Issue / Number:81
Start Page:064907
Audience:Not Specified
Intended Educational Use:No
Abstract / Description: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.
Classification / Thesaurus:NA49
Comment of the Author/Creator:31 pages, 11 figures
External Publication Status:published
Document Type:Article
Communicated by:N.N.
Affiliations:
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