Probing Nuclear Deformation and Clustered Structure Through Photon Anisotropic Flow in Relativistic Nuclear Collisions

Abstract

Relativistic collisions of nuclei with different intrinsic structures provide a unique opportunity to study how nuclear geometry and deformation influence the initial conditions and the subsequent evolution of the hot and dense quark gluon plasma created in such collisions. Observables measured in collisions involving deformed uranium nuclei, clustered light nuclei such as carbon and oxygen, and isobaric systems such as ruthenium and zirconium offer complementary insights into the properties of the initial state, extending the information obtained from collisions of nearly spherical nuclei. The deformation and possible cluster substructures in the colliding nuclei are expected to generate distinct initial geometric features in the overlap region, while isobaric collisions enable the study of nuclear structure effects in systems with nearly identical mass numbers. These differences influence the initial spatial anisotropies, which subsequently translate into final state momentum anisotropies of the produced particles. The production and anisotropic flow vn of thermal photons serve as an effective probe of early stage dynamics in relativistic nuclear collisions. A systematic analysis of photon vn in different collision systems can therefore help identify the effects of nuclear deformation and clustering in the initial state.