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Decoding the phase structure of QCD via particle production at high energy


Recent studies based on lattice Monte Carlo simulations of quantum chromodynamics (QCD)—the theory of strong interactions—have demonstrated that at high temperature there is a phase change from confined hadronic matter to a deconfined quark–gluon plasma in which quarks and gluons can travel distances that greatly exceed the size of hadrons. Here we show that the phase structure of such strongly interacting matter can be decoded by analysing particle production in high-energy nuclear collisions within the framework of statistical hadronization, which accounts for the thermal distribution of particle species. Our results represent a phenomenological determination of the location of the phase boundary of strongly interacting matter, and imply quark–hadron duality at this boundary.

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Fig. 1: Hadron abundances and predictions of the statistical hadronization model.
Fig. 2: Mass dependence of hadron yields compared with predictions of the statistical hadronization model.
Fig. 3: Energy dependence of chemical freeze-out parameters Tcf and μb.
Fig. 4: Collision-energy dependence of the relative abundance of several hadron species.
Fig. 5: Phenomenological phase diagram of strongly interacting matter.
Fig. 6: Relative production of ψ(2S) and J/ψ mesons as a function of collision energy.
Fig. 7: The nuclear modification factor RAA for inclusive J/ψ production.
Fig. 8: Multiplicity dependence of production ratio of bottomonium states ϒ(2S) and ϒ(1S).


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K.R. acknowledges support by the Polish National Science Centre under Maestro grant DEC-2013/10/A/ST2/00106. This work is part of and supported by the DFG Collaborative Research Centre ‘SFB1225/ISOQUANT’.

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All authors contributed equally to the physics analysis and to writing the manuscript.

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Correspondence to Peter Braun-Munzinger.

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Andronic, A., Braun-Munzinger, P., Redlich, K. et al. Decoding the phase structure of QCD via particle production at high energy. Nature 561, 321–330 (2018).

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  • Ultra-relativistic Nuclear Collisions
  • Statistical Hadronization Model
  • Relativistic Heavy Ion Collider (RHIC)
  • Hadron Yield
  • Heavy Quark

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