School of Physics & Astronomy

# Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at √s = 0.9 and 2.36TeV" CMS Collaboration

(including Yuichi Kubota, Jeremy Mans and Roger Rusack) in the Journal of High Energy Physics, Volume 2010, Number 2 / February, 2010.

Measurements of inclusive charged-hadron transverse-momentum and pseudorapidity distributions are presented for proton-proton collisions at √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  and pp collisions. The results at 2.36 TeV represent the highest-energy measurements at a particle collider to date.