Measurements of jet multiplicity and jet transverse momentum in multijet events in proton–proton collisions at \({\sqrt{s}=13\, \text {TeV}}\)

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.