Top-Quark pT-Spectra at LHC and Flavor Independence of z-Scaling

Abstract

New results of analysis of top-quark differential cross sections obtained by the CMS and ATLAS Collaborations in pp collisions at the LHC in the framework of z-scaling approach are presented. The spectra are measured over a wide range of collision energy √s = 7, 8, 13 TeV and transverse momentum pT = 30−1000 GeV/c of top-quark using leptonic and jet decay modes. The LHC data on transverse momentum of the top-quark spectra are compared with the Tevatron data obtained by the D∅ Collaboration in pp̅ collisions at√s = 1.96 GeV. Flavour independence of the scaling function ψ(z) in pp and pp̅ interactions over a wide collision energy range√s = 19 − 13000 GeV is verified. This property of ψ(z) was found for different hadrons from π-meson up to ϒ particle. The flavour independence of ψ(z) is used as indication on self-similarity of top-quark production. A tendency to saturation of ψ(z) at low z for top-quark is demonstrated. We anticipate that data on low- and high-pT inclusive spectra of top-quark production at LHC energies could be of interest for verification of the self-similarity over a wide range of masses and different flavour content of produced particles.