Abstract
Rapidity-odd directed flow () measurements for charged pions, protons, and antiprotons near midrapidity () are reported in , 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.
- Received 13 January 2014
DOI:https://doi.org/10.1103/PhysRevLett.112.162301
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