Charged-particle production was studied in proton-proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range |$\eta$| < 1.4. In the central region (|$\eta$| < 0.5), at 0.9 TeV, we measure charged-particle pseudorapidity density ${\rm d}N_{\rm ch}/{\rm d}\eta$ = 3.02 +- 0.01 (stat.) +0.08 -0.05 (syst.) for inelastic interactions, and ${\rm d}N_{\rm ch}/{\rm d}\eta$ = 3.58 +- 0.01 (stat.) +0.12 -0.12 (syst.) for non-single-diffractive interactions. At 2.36 TeV, we find ${\rm d}N_{\rm ch}/{\rm d}\eta$ = 3.77 +- 0.01 (stat.) +0.25 -0.12 (syst.) for inelastic, and${\rm d}N_{\rm ch}/{\rm d}\eta$ = 4.43 +- 0.01 (stat.) +0.17 -0.12 (syst.) for non-single-diffractive collisions. The relative increase in charged-particle multiplicity from the lower to higher energy is 24.7% +- 0.5% (stat.) +5.7% -2.8% (syst.) for inelastic and 23.7% +- 0.5% (stat.) +4.6% -1.1% (syst.) for non-single-diffractive interactions. This increase is consistent with that reported by the CMS collaboration for non-single-diffractive events and larger than that found by a number of commonly used models. The multiplicity distribution was measured in different pseudorapidity intervals and studied in terms of KNO variables at both energies. The results are compared to proton-antiproton data and to model predictions.
Eur. Phys. J. C 68 (2010) 89-108
HEP Data
e-Print: arXiv:1004.3034 | PDF | inSPIRE
CERN Record