Speaker
Description
High-energy collisions are a promising tool to study nuclear deformation, but they pose a conceptual challenge: nuclei are quantum objects whose ground state is a superposition of intrinsic deformed configurations at orientations. How does this quantum nature affect the semi-classical geometry of the Quark-Gluon Plasma fireball? I will argue that the collision does not project the nucleus onto a single orientation. Instead, it simultaneously measures the positions of many nucleons, encoding "off-diagonal" information from the collective wavefunction into the fireball's shape. I will introduce a minimal extension to the Monte Carlo Glauber model to go beyond the single-particle density and quantify this effect. Using this framework, I will estimate the impact of "orientation superposition" on the initial geometry for both light (Ne-20) and heavy nuclei. Finally, I will discuss how the manifestation of deformation differs across central collisions, ultra-peripheral collisions (UPCs), and low-energy collisions.