2014/10/09 by Adare, A., Afanasiev, S., Aidala, C. +619
#FOS: Physical sciences #Nuclear Experiment (nucl-ex)
paper · doi:10.48550/arxiv.1410.2559
Two-pion interferometry measurements are used to extract the Gaussian radii R\rm out, R\rm side, and R\rm long, of the pion emission sources produced in Cu+Cu and Au+Au collisions at several beam collision energies √s_NN at PHENIX. The extracted radii, which are compared to recent STAR and ALICE data, show characteristic scaling patterns as a function of the initial transverse size R of the collision systems and the transverse mass mT of the emitted pion pairs, consistent with hydrodynamiclike expansion. Specific combinations of the three-dimensional radii that are sensitive to the medium expansion velocity and lifetime, and the pion emission time duration show nonmonotonic √s_NN dependencies. The nonmonotonic behaviors exhibited by these quantities point to a softening of the equation of state that may coincide with the critical end point in the phase diagram for nuclear matter.