Parton Energy Loss in Cu + Au and U + U Collisions at √ s_NN = 200 and 193 GeV, Respectively

In this study, the effective fractional parton energy losses S_loss~ in the quark-gluon medium formed in U + U and Cu + Au collisions at initial energies √ s_NN = \,\,~193~ and 200 GeV, respectively, were obtained on the basis of nuclear modification factors and elliptic flows of π ⁰ -mesons. The dependences of S_loss~ on the azimuthal emission angle of π ⁰ -mesons (relative to the reaction plane) and on the effective path length of partons in the quark-gluon medium were constructed. The dependences of parton stopping powers in the quark-gluon medium on the azimuthal emission angle of partons (relative to the reaction plane) were estimated for Cu + Au and U + U collisions at √ s_NN = 200 and 193 GeV, respectively.