Probing Quantum Interference and Spin Effects in Parton Showers through Multi-Point Energy-Energy Correlators*

When high-energy collisions occur at the LHC, energetic partons like quarks and gluons manifest as jets. This jet production process is initiated with a parton shower, which obscures critical information about the original quarks and gluons. This project develops an ATLAS measurement of multi-point energy-energy correlators (EECs) observables. This will directly allow quantum aspects to be probed in the jet substructure, focusing on spin interference effects. This project employed multi-point EECs using generated data to identify quantum interference patterns arising from parton spin dynamics in the angular distribution of energy. Gluon-initiated jets consistently displayed greater energy density than quark-initiated jets, aligning with the theoretical energy ratio. However, our observations showed a phase shift of π/2 from the theoretically predicted pattern. Observed interference patterns from Monte Carlo simulations revealed disparities, indicating potential inconsistencies in numerical methods or the current theoretical models. The reason for this inconsistency has yet to be determined. The study concludes that a deeper understanding of the phenomenon is necessary, emphasizing the requirement for additional exploration.