Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at sqrt{s} = 0.9 and 2.36 TeV

Abstract

Measurements of inclusive charged-hadron transverse-momentum and pseudorapidity distributions are presented for proton-proton collisions at sqrt{s} = 0.9 and 2.36 TeV. The data were collected with the CMS detector during the LHC commissioning in December 2009. For non-single-diffractive interactions, the average charged-hadron transverse momentum is measured to be 0.46 ± 0.01 (stat.) ± 0.01 (syst.) GeV/ c at 0.9 TeV and 0.50 ± 0.01 (stat.) ± 0.01 (syst.) GeV/ c at 2.36 TeV, for pseudorapidities between -2.4 and +2.4. At these energies, the measured pseudorapidity densities in the central region, dN _ch/ dη|_|η|<0.5, are 3:48 ± 0:02 (stat.) ± 0.13 (syst.) and 4:47 ± 0:04 (stat.) ± 0.16 (syst.), respectively. The results at 0.9 TeV are in agreement with previous measurements and confirm the expectation of near equal hadron production in overline p p and pp collisions. The results at 2.36 TeV represent the highest-energy measurements at a particle collider to date.