Measurements of identified particle anisotropic flow in Cu + Au and U + U collisions by PHENIX experiment

In this paper, new measurements of anisotropic flow (v1,v2) for identified particles such as pions and protons in Cu + Au collisions at sNN=200 GeV and U + U collisions at sNN=193 GeV are reported. The anisotropic flow is studied as a function of pT and centrality in these two collision systems. In ultra-central U + U collisions (0-2% centrality), v2 of protons shows a weak pT dependence for pT<1.0 GeV/c. A positive v1 for charged pions is observed for pT>1 GeV/c with respect to the first-order event plane, the angle of which is determined by the Au-going spectators. The scaling of identified particle v2 with the number of valence quarks (nq) has been observed in these two collision systems, with the transverse kinetic energy.