Insights into Nuclear Geometry and Initial Conditions of Heavy-Ion Collisions from ATLAS

by Somadutta Bhatta (Stony Brook University (US))

Tuesday 11 Mar 2025, 10:00 → 11:30 Europe/Zurich

4/2-037 - TH meeting room (CERN)

One of the central limitations on constraining the properties of Quark-Gluon Plasma (QGP) formed in heavy-ion collisions stems from uncertainties in modeling the initial conditions. Recent measurements show that the overlap region captures a snapshot of nuclear geometry on an event-by-event basis, which, in turn, can be leveraged to constrain other aspects of the initial condition better. In this talk, I will present ATLAS measurements of flow and its correlation with mean transverse momentum to constrain nuclear deformation in 129Xe. In addition, various sources of initial state fluctuations exist in the initial state that remain challenging to characterize. To tackle this, recent ATLAS measurements establish transverse momentum fluctuations as a powerful tool to disentangle different initial state fluctuations. Additionally, these measurements provide a potential method to  extract the speed of sound in the medium, though with certain limitations. Lastly, I will discuss how these findings pave the way for fresh perspectives and innovative approaches for future studies on space-time evolution of heavy-ion collisions.

CERN-TH-Som.pdf