Nonperturbative Effects in Energy Correlators: From Characterizing Confinement Transition to Improving $α_s$ Extraction

Abstract: Energy correlators provide a powerful observable to study fragmentation dynamics in QCD. We demonstrate that the leading nonperturbative corrections for projected $N$-point energy correlators are described by the same universal parameter for any $N$, which has already been determined from other event shape fits. Including renormalon-free nonperturbative corrections substantially improves theoretical predictions of energy correlators, notably the transition into the confining region at small angles. Nonperturbative corrections are shown to have a significant impact on $\alpha_s$ extractions.