Initial state and evolution of the hot and dense medium produced in isobaric collisions at GeV at the BNL Relativistic Heavy Ion Collider
Phys. Rev. C 113, 044901 – Published 1 April, 2026
DOI: https://doi.org/10.1103/xr9q-sr9q
Abstract
Isobaric collisions provide a unique opportunity to investigate how variations in the charge to mass ratio affect the final state observables produced in relativistic heavy ion collisions. Most importantly, isobaric systems that differ in their nuclear structure offer valuable insights into the underlying nuclear geometries, making them powerful tools to probe the role of nuclear structure using heavy ion collisions. We study the initial state and evolution of the hot and dense medium formed in and collisions at GeV at RHIC using a relativistic hydrodynamical model. The initial geometry of the two isobaric collisions is found to influence the evolution of the hot and dense medium produced. The sensitivity of photon production, charged particle spectra, and anisotropic flow coefficients () to the initial geometry, including different orientations of the isobaric set, has been studied in detail. Significant variations in anisotropic flow of photons and hadrons are observed, highlighting the role of nuclear deformation in shaping final state observables. Moreover, photon anisotropic flow is found to be considerably more sensitive to the initial state than charged particle anisotropic flow, indicating that photon measurements in isobaric collisions have strong potential to constrain initial state modeling and improve our understanding of quark-gluon plasma properties in such systems.
