Measurements of flow in ¹⁶O+¹⁶O and ²⁰Ne+²⁰Ne by the ATLAS Collaboration at the Large Hadron Collider

Measurements of the azimuthal anisotropy, or “flow,” in ¹⁶O+¹⁶O and ²⁰Ne+²⁰Ne collisions at √s_NN = 5.36 TeV by the ATLAS Collaboration at the Large Hadron Collider (LHC). Collective flow has historically been observed in heavy-ion collisions and has been well-established as a signature of Quark Gluon Plasma (QGP) formation. Smaller systems have also demonstrated significant flow-like properties, though the nature of these flow signals is significantly limited by ambiguities in the description of the initial-state conditions of the colliding system. The LHC recently completed its first light-ion program, in which oxygen-oxygen and neon-neon collisions were produced for the first time at a nucleon-nucleon center-of-mass energy of 5.36 TeV. This analysis of the azimuthal anisotropy in both ¹⁶O+¹⁶O and ²⁰Ne+²⁰Ne collisions provides insight into the collective behavior of small, dense systems of nuclear matter. Additionally, a comparison between the two systems offers new information on the role of nuclear structure in QGP dynamics, given that ¹⁶O and ²⁰Ne are similar in size but different in geometry.