Directed and elliptic flows of neutrons and light-charged particles were measured for the reaction Au197+Au197 at 400 MeV/nucleon incident energy within the ASY-EOS experimental campaign at the GSI laboratory. The detection system consisted of the Large Area Neutron Detector (LAND), combined with parts of the CHIMERA multidetector, the ALADIN Time-of-flight Wall, and the Washington University Microball detector. The latter three arrays were used for the event characterization and reaction-plane reconstruction. In addition, an array of triple telescopes, KRATTA was used for complementary measurements of the isotopic composition and flows of light-charged particles. From the comparison of the elliptic-flow ratio of neutrons with respect to charged particles with UrQMD predictions, a value γ=0.72±0.19 is obtained for the power-law coefficient describing the density dependence of the potential part in the parametrization of the symmetry energy. It represents a new and more stringent constraint for the regime of suprasaturation density and confirms, with a considerably smaller uncertainty, the moderately soft to linear density dependence deduced from the earlier FOPI-LAND data. The densities probed are shown to reach beyond twice saturation.
|Titolo:||Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density|
|Autori interni:||GUAZZONI, CHIARA|
|Data di pubblicazione:||2016|
|Rivista:||PHYSICAL REVIEW C|
|Appare nelle tipologie:||01.1 Articolo in Rivista|
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|PhysRevC.94.034608.pdf||3.92 MB||Adobe PDF||PDF editoriale||Accesso riservato|