Charged particle transverse momentum spectra in pp collisions at √s = 0.9 and 7 TeV

Abstract

The charged particle transverse momentum (p _T) spectra are presented for pp collisions at √s =09 and 7 TeV. The data samples were collected with the CMS detector at the LHC and correspond to integrated luminosities of 231 pb^-1 and 2.96 pb^-1, respectively. Calorimeter-based high-transverse-energy triggers are employed to enhance the statistical reach of the high-p _T measurements. The results are compared with leading and next-to-leading order QCD and with an empirical scaling of measurements at different collision energies using the scaling variable x_T≡ 2_pT/√s over the p _T range up to 200 GeV/c. Using a combination of x _T scaling and direct interpolation at fixed p _T, a reference transverse momentum spectrum at √s = 276 TeV is constructed, which can be used for studying high-p _T particle suppression in the dense QCD medium produced in heavy-ion collisions at that centre-of-mass energy.