Longitudinal flow decorrelation in heavy-ion collision at RHIC energies using a multi-phase transport model

Abstract

We present a comprehensive study on the longitudinal flow decorrelation in heavy-ion collisions at the RHIC Beam Energy Scan (BES) energies, spanning from \(\sqrt{s_{NN}}\) = 11.5 to 200 GeV in Au+Au collisions, using the A Multi-Phase Transport (AMPT) model. Our investigation entails measuring the second and third order factorization ratios (\(r_{2}\) and \(r_{3}\)) across all these energies. We observed that the decorrelation is stronger at lower energies compared to higher collision energies, with this energy dependence trend being more prominent in \(r_{3}\). Additionally, we analyze the contributions of flow-plane and flow magnitude decorrelation to the overall decorrelation phenomenon. Notably, our findings reveal that flow plane decorrelation exhibits a dominant contribution compared to flow magnitude decorrelation. Moreover, we incorporate a recently proposed observable, the four particle cumulant (\(T_{2}\)), which remains resilient to non-flow effects and exhibits sensitivity to different decorrelation patterns. Through the measurement of \(T_{2}\), we consistently observe an S-shaped or torqued decorrelation across all energy ranges.