Towards the Precision Nucleon Energy-Energy Correlator in Lepton-Ion Collisions

The nucleon energy-energy correlator (NEEC) was proposed in 2209.02080 as a new way of studying nucleon intrinsic dynamics. In this work, we present a detailed derivation of the factorization theorem that enables the measurement of the unpolarized NEEC in lepton-ion collisions. As a first step towards a precise measurement of this quantity, we obtained the next-to-leading-logarithmic (NLL, $\sim{\cal O}(\alpha_s^n L^{n-1})$) resummation in a concise analytic form, and predicted the analytic $\theta$-angle distribution at ${\cal O}(\alpha^2_s)$. Extending our analytic resummation formula to higher logarithmic accuracy and the factorization theorem to hadron-hadron collisions is straightforward.