The Breit-Wheeler Process from RHIC's Legacy to the EIC

Among the scientific legacy of RHIC - a machine built to unlock secrets of nuclear matter - is a potentially unexpected triumph in the annals of quantum electrodynamics. Predicted in 1934 by Breit and Wheeler, the direct conversion of light into matter via photon-photon collisions is among the most fundamental predictions of quantum electrodynamics, yet it remained experimentally elusive for nearly a century. However, the ultra-Lorentz boosted electromagnetic fields surrounding fast-moving heavy atomic nuclei provide a source of quasi-real photons with the necessary intensity and energy to achieve this elusive process and reveal its characteristic signature predicted since the early days of quantum mechanics. This achievement not only validates a cornerstone in our understanding of quantum electrodynamics, but has also opened a new window for precision studies of photon–photon dynamics and photon-nucleus interactions. This talk will reflect on the impact of these measurements as part of RHIC's scientific legacy and look ahead to how they herald aspects of the future physics program of the Electron-Ion Collider.