Speaker
Description
Correlation functions of generalized detectors provide a broad class of measurements relevant for heavy-ion jets, including the well-known energy–energy correlator (EEC), its energy-squared variant (E2E2C), and charged energy correlators. In this talk, we show that correlators of generalized detectors admit a universal theoretical description based on the light-ray operator product expansion (OPE) and track functions. Medium-driven modifications appear as an enhancement of higher-twist matrix elements in the light-ray OPE, making these observables directly sensitive to the heavy-ion environment. We validate this framework against CMS measurements of the EEC and E2E2C, revealing an enhanced quark-jet fraction in 0–10% central Pb–Pb collisions relative to p–p, which cannot be explained by nuclear parton distribution functions alone.