Parton Energy Loss in Cu + Au and U + U Collisions at $$\sqrt {{{s}_{{NN}}}} $$ = 200 and 193 GeV, Respectively

In this study, the effective fractional parton energy losses $${{S}_{{{\\text{loss}}}}}~$$ in the quark-gluon medium formed in U + U and Cu + Au collisions at initial energies $$\\sqrt {{{s}_{{NN}}}} = \\,\\,~193~$$ and 200 GeV, respectively, were obtained on the basis of nuclear modification factors and elliptic flows of $${{\\pi }^{0}}$$ -mesons. The dependences of $${{S}_{{{\\text{loss}}}}}~$$ on the azimuthal emission angle of $${{\\pi }^{0}}$$ -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 $$\\sqrt {{{s}_{{NN}}}} $$ = 200 and 193 GeV, respectively.