Researchers have developed a new model, named WAGASHI, to study the non-perturbative production of quark-antiquark pairs and the subsequent quark dynamics in the earliest glasma stage of relativistic heavy-ion collisions. This model combines classical Yang-Mills glasma evolution, particle transport described by the Wong equation, and Schwinger pair production, all simulated on an event-by-event basis. The goal is to better understand how the quark-gluon plasma (QGP), a phase of matter that briefly existed after the Big Bang, forms and evolves.

The WAGASHI results indicate that a significant number of quarks, comparable to the final hadron yields, are produced already during the glasma stage. These quarks undergo substantial momentum broadening and spin randomization. This finding suggests a significant contribution to the rapid equilibration of the quark-gluon plasma in its early stages. The model has also allowed for the determination of event-by-event distributions of baryon number, electric charge, strangeness, and spin polarization in lead-lead (Pb-Pb) and oxygen-oxygen (O-O) collisions at LHC energies.

Notably, large fluctuations in the distributions were observed for the smaller O-O collision system. These results provide crucial dynamic initial conditions for the subsequent hydrodynamic evolution of the quark-gluon plasma. Understanding the glasma phase is fundamental to unraveling the properties of the QGP and how matter behaved in the universe's initial moments, offering a window into quantum chromodynamics under extreme conditions.