Revealing the harmonic structure of nuclear two-body correlations in high-energy heavy-ion collisions

Abstract: Smashing nuclei at ultrarelativistic speeds and analyzing the momentum distribution of outgoing debris provides a powerful method to probe the many-body properties of the incoming nuclear ground states. Within a perturbative description of initial-state fluctuations in the quark-gluon plasma, we express the measurement of anisotropic flow in ultra-central heavy-ion collisions as the quantum-mechanical average of a specific set of operators measuring the harmonic structure of the two-body azimuthal correlations among nucleons in the colliding states. These observables shed a new light on spatial correlations in atomic nuclei, while enabling us to test the complementary pictures of nuclear structure delivered by low- and high-energy experiments on the basis of state-of-the-art theoretical approaches rooted in quantum chromodynamics.