CMS-PAS-FSQ-12-026

CMS-PAS-FSQ-12-026
Pseudorapidity and leading transverse momentum distributions of charged particles in pp collisions at 8 TeV
CMS Collaboration
2013

Abstract: The pseudorapidity and leading transverse momentum distributions of charged particles in proton-proton collisions at $\sqrt{s}$ = 8 TeV are measured in the pseudorapidity range $\|\eta\|<2.4$ , by the CMS detector. The data correspond to an integrated luminosity of 17.4 nb $^{-1}$ . Events were triggered by the TOTEM T2 telescopes that cover the pseudorapidity range .3<\|\eta\|<6.5 $for reconstructed tracks with$ p_{T}>40 $MeV. The measurement of the pseudorapidity distributions was performed for primary charged particles with$ p_T>0.1 $GeV and$ p_T>1 $GeV, for two different conditions: an inclusive sample obtained by requiring tracks reconstructed in the acceptance of the TOTEM T2 telescopes in either hemisphere, and a sample enhanced in non-single diffractive dissociation events by requiring tracks in T2 in both forward and backward hemispheres. The$ p_T $distribution of the leading tracks in the central region is also measured. The distribution integrated over the leading track transverse momentum, above a$ p_\rm{{T,min}} $value, shows a transition from a steeply falling distribution at large$ p_T $(perturbative region) to a flat distribution at small$ p_T $(non-perturbative region) for$ p_\rm{{T,min}}$ of a few GeV. This region is not well described by current Monte Carlo event generators.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; Figures are available from the CDS record. These preliminary results are superseded in this paper, EPJC 74 (2014) 3053.

Compact Muon Solenoid
LHC, CERN