Angular correlations and polarization in $Z$+jet production at the LHC

Abstract

Precision studies at the LHC increasingly require theoretical control over QCD radiation beyond fixed-order perturbation theory, particularly in final states characterised by large separations in rapidity. High-energy logarithms can generate corrections at the ten-percent level even for electroweak-scale observables, as recently observed in Higgs production, motivating their systematic inclusion in precision analyses. We investigate this regime through Drell$-$Yan plus jet production, with particular emphasis on $Z$-boson final states and their angular and polarisation structure. High-energy logarithms are resummed at next-to-leading logarithmic accuracy and consistently combined with NLO fixed-order information. Beyond inclusive rapidity and transverse-momentum spectra, the framework resolves the azimuthal harmonic content of the process, whose pattern is reshaped by the transition from leading- to next-to-leading-order emission dynamics. We further develop the JETHAD$-$DYnamis$-$POWHEG strategy towards realistic lepton-level predictions, retaining spin correlations, decay-angle information, and experimentally accessible kinematics. This programme establishes $Z$+jet production as a precision probe of high-energy QCD dynamics for Run~3 and the HL-LHC.