Speaker
Description
Energy-energy correlators (EECs) have recently emerged as powerful, rigorously proven infrared- and collinear-safe (IRC-safe) observables for probing QCD dynamics in the vacuum. However, their IRC safety and factorization properties in the presence of a nuclear medium have never been established. In this talk, I will present the first proof of QCD factorization at next-to-leading order (NLO), in the presence of nuclear medium, for an energy-flow observable in a real scattering process. Working within a high-twist framework, we calculate the twist-4 contributions to the angular width of the one-point energy correlator (OPEC) in semi-inclusive deep inelastic electron-ion scattering, explicitly demonstrating its IRC safety for medium-enhanced effects. We show that the OPEC angular spreading width is a highly sensitive, hadronization-free probe of transverse momentum broadening in cold nuclear matter. This NLO factorization framework establishes a critical theoretical foundation expected to be extended to a wide array of high-energy processes in nuclear environments, and paves the way for global analyses of nuclear property using OPEC.