Abstract

Elliptic flow (v(2)) values for identified particles at midrapidity in Au + Au collisions, measured by the STAR experiment in the beam energy scan at RHIC at root s(NN) = 7.7-62.4 GeV, are presented. A beamenergy-dependent difference of the values of v(2) between particles and corresponding antiparticles was observed. The difference increases with decreasing beam energy and is larger for baryons compared to mesons. This implies that, at lower energies, particles and antiparticles are not consistent with the universal number-of-constituent-quark scaling of v(2) that was observed at root s(NN) = 200 GeV. DOI: 10.1103/PhysRevLett.110.142301