Event topology in heavy-ion collisions: The initial spatial anisotropy and final azimuthal anisotropy

Abstract

In this contribution, we discuss the use of transverse spherocity in Pb–Pb collisions at sNN = 5.02 TeV using AMPT to study initial state spatial anisotropy and final state momentum space azimuthal anisotropy. Event selections based on transverse spherocity are found to affect the values of the flow coefficients, such as elliptic flow (v2[jls-end-space/]) and triangular flow (v3[jls-end-space/]). A crossing point in transverse momentum between v2 and v3 is also reported, which is found to be varying with transverse spherocity selections. Finally, we show that the kinetic freeze-out temperature and mean transverse radial flow velocity strongly depend on the transverse spherocity selection. This study aims to establish transverse spherocity as an event-shape observable that can be used throughout collision systems. © 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.