Speaker
Description
We study the impact of fiducial acceptance cuts on Energy-Energy Correlators (EECs) in $e^+e^-$ annihilation into hadrons. Experimental measurements of EECs typically impose an angular acceptance defined with respect to oriented event-shape axes, such as thrust or sphericity, and correct the resulting phase-space loss using Monte Carlo efficiency factors.
We instead adopt a fully analytic approach and compute the fiducial EEC to $O(\alpha_s)$ using thrust and sphericity axes. We find that the impact of finite angular acceptance on measured EECs can reach up to 3$\%$ for both axes and induce nontrivial shape distortions that are uncontrolled in MC. We further use symmetry arguments to decompose the all-order EEC in terms of scalar structure functions, and propose a data-driven defiducialization strategy (inspired by similar techniques at the Tevatron and the LHC) to rigorously reconstruct the full phase-space EEC directly from differential measurements, eliminating the need for MC efficiency corrections.