Charged particle transverse momentum spectra in pp collisions at sqrt(s) = 0.9 and 7 TeV

TL;DR

This paper presents charged particle transverse momentum spectra in proton-proton collisions at 0.9 and 7 TeV, using CMS data, and constructs a reference spectrum at 2.76 TeV for heavy-ion collision studies.

Contribution

It provides detailed pT spectra at two energies and develops a method to interpolate a reference spectrum at 2.76 TeV for high-pT suppression analysis.

Findings

pT spectra measured up to 200 GeV/c

xT scaling used for energy comparison

reference spectrum at 2.76 TeV constructed

Abstract

The charged particle transverse momentum (pT) spectra are presented for pp collisions at sqrt(s)=0.9 and 7 TeV. The data samples were collected with the CMS detector at the LHC and correspond to integrated luminosities of 231 inverse microbarns and 2.96 inverse picobarns, respectively. Calorimeter-based high-transverse-energy triggers are employed to enhance the statistical reach of the high-pT measurements. The results are compared with both leading-order QCD and with an empirical scaling of measurements at different collision energies using the scaling variable xT = 2 pT/sqrt(s) over the pT range up to 200 GeV/c. Using a combination of xT scaling and direct interpolation at fixed pT, a reference transverse momentum spectrum at sqrt(s)=2.76 TeV is constructed, which can be used for studying high-pT particle suppression in the dense QCD medium produced in heavy-ion collisions at that centre-of-mass energy.