Initial-state-driven spin correlations in high-energy nuclear collisions

• DOI: 10.48550/arxiv.2502.13102
• Publication Date: 2025-02-18
• Authors: Giuliano Giacalone; Enrico Speranza
• Keywords: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology; High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory; FOS: Physical sciences; Nuclear Experiment (nucl-ex); Nuclear Experiment; High Energy Physics - Experiment

In the study of spin-polarization phenomena in heavy-ion collisions, it is typically assumed that final-state particles are polarized through thermal vorticity and shear. this sense, polarization a effect. Here, we propose different mechanism. We postulate collision spin-carrying nucleons generates an initial transverse spin density, inducing net QCD fireball along random direction. If conserved throughout evolution fireball, should exhibit measurable polarization. Within wounded nucleon picture, estimate initial-state fluctuations induce $\Lambda$ baryons which around $1\%$ central collisions over $10\%$ noncentral significantly exceeding contributions from introduce two-particle angular correlation observable designed to reveal net-spin fluctuations, emphasize main signatures look for experiments. argue discovery these would have profound implications nuclear structure our understanding relativistic hydrodynamics.