Charged particle multiplicities in pp interactions at sqrt(s) = 0.9, 2.36, and 7 TeV
Journal Article

Published: Wednesday, January 19, 2011
Citation: Journal of High Energy Physics, Volume 1101, Pages 079 1011.5531

Authors (1 total): J. Rohlf


Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of Ös = 0.9s=09 , 2.36, and 7 TeV, in five pseudorapidity ranges from |η| < 0.5 to |η| < 2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7 TeV run in 2010. The multiplicity distribution at Ös = 0.9  \textTeV s=09TeV  is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with Öss  is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling that has been observed at lower energies.