Tracing Electromagnetic Response through Charge Splitting of Directed Flow in the Quark-Gluon Plasma
Experimentally observed charge splitting of directed flow, $\Delta v_1\equiv v_1(h^+)-v_1(h^-)$, exhibits both a sign reversal at midrapidity and the amplitude change from Au+Au collisions at $\sqrt{s_{\rm NN}}=200$ GeV to Pb+Pb at $\sqrt{s_{\rm NN}}=5.02$ TeV. We study this behavior within a unified $(3+1)$-dimensiona...