Measurements of jet multiplicity and jet transverse momentum in multijet events in proton–proton collisions at

Multijet events at large transverse momentum ($$p_{\textrm{T}}$$) are measured at $$\sqrt{s}=13\,\text {TeV} $$ using data recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of $$36.3{\,\text {fb}^{-1}} $$. The multiplicity of jets with $$p_{\textrm{T}} >50\,\text {GeV} $$ that are produced in association with a high-$$p_{\textrm{T}}$$ dijet system is measured in various ranges of the $$p_{\textrm{T}}$$ of the jet with the highest transverse momentum and as a function of the azimuthal angle difference $$\varDelta \phi _{1,2}$$ between the two highest $$p_{\textrm{T}}$$ jets in the dijet system. The differential production cross sections are measured as a function of the transverse momenta of the four highest $$p_{\textrm{T}}$$ jets. The measurements are compared with leading and next-to-leading order matrix element calculations supplemented with simulations of parton shower, hadronization, and multiparton interactions. In addition, the measurements are compared with next-to-leading order matrix element calculations combined with transverse-momentum dependent parton densities and transverse-momentum dependent parton shower