Two-Jet Correlations in Multijet Events in the Regge Limit of QCD

A new method for matching calculations in the leading approximation in the kT-factorization approach with the higher-order contributions of perturbation theory, which appear due to the emission of additional hard partons, is proposed. In the proposed method, azimuthal correlations between the leading and subleading jets in a multijet event are considered. The calculations are carried out within the parton Reggeization approach (PRA) that is based on kT-factorization of hard processes in multi-Regge kinematics, the Kimber–Martin–Ryskin model for nonintegrated parton distribution functions (nPDF), and the effective field theory of Reggeized gluons and quarks proposed by L.N. Lipatov. Theoretical predictions are compared with the CMS collaboration data collected at the Large Hadron Collider at energy $$\sqrt S = 13$$ TeV.