Investigation of the initial geometry description using collectivity in the AMPT model

The motivation of geometry engineering with proton, deuteron, and helium-3 projectiles at relativistic heavy-ion collider (RHIC) is to investigate the relation between initial geometry and final momentum anisotropy, which is thought to be strong evidence of quark–gluon plasma. PHENIX Collaboration shows a hierarchy of elliptic and triangular flow in p/d/ \(^{3}\) $_{}^3$ He+Au collisions that follow a hierarchy of eccentricity described by the Monte Carlo Glauber model, whereas STAR Collaboration shows a different trend in the triangular flow results. For a complete understanding of the results, a detailed microscopic description, such as sub-nucleon geometry and area of energy deposition, becomes more important. A multiphase transport model (AMPT) can qualitatively describe the collective behavior with scatterings at partonic and hadronic stages. We utilize the AMPT to simulate small systems and investigate the relation between initial geometry and final momentum anisotropy with different geometry descriptions.