Determination of the strong coupling constant and the Collins-Soper kernel from the energy-energy correlator in $e^{+}{e}^{-}$ collisions

We have conducted the first simultaneous global fit of the strong coupling constant ${\alpha }_s$ and the Collins-Soper (CS) kernel using the energy-energy correlators (EEC) of $e^{+}{e}^{-}$ collisions in the back-to-back limit. This analysis, based on the transverse-momentum-dependent (TMD) factorization of EEC at next-to-next-to-next-to-leading logarithmic (${\mathrm{N}}^3\mathrm{L}\mathrm{L}$) accuracy, yields ${\alpha }_s$ consistent with the world average. We have tested two different parametrizations for the non-perturbative CS kernel and found both to align with results obtained from lattice QCD and fits on semi-inclusive deep inelastic scattering and Drell-Yan process.