Pseudorapidity dependence of long-range two-particle correlations in pPb collisions with CMS

Collaboration
2014
14 pages
Report number:
  • CMS-PAS-HIN-14-008
Experiments:

Citations per year

20142015201613
Abstract:
CMS measurements of two-particle correlations of charged particles have previously been published for proton-proton (pp), proton-lead (pPb), and lead-lead (PbPb) systems. This paper studies how the two-particle correlations depend on the relative pseudorapidity of the trigger and associate particles (Δη\Delta\eta) utilizing a narrow η\eta range for the trigger particle. The data were collected during the 2013 pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The near-side (Δϕ0\Delta\phi\approx 0) jet-like correlation is assumed to be of a generalized Gaussian shape in Δη\Delta\eta, and fitted with a pedestal long-range pseudorapidity correlation (ridge) in high-multiplicity collisions. The latter is modeled by combinatorial background multiplied by a linear function in Δη\Delta\eta, which is found to describe the data well. The jet correlations are subtracted, and the remaining ridge correlations are studied versus Δη\Delta\eta for small seperation in relative azimuthal angle. Furthermore, the Fourier coefficients of the two-particle correlations are extracted for high-multiplicity collisions, with and without subtraction of jet contributions approximated by the scaled low-multiplicity collision data. The η\eta dependence of the azimuthal anisotropy parameters is reported.
Note:
  • Preliminary results
  • Data
  • correlation: two-particle
  • jet: correlation
  • rapidity: correlation: long-range
  • charged particle: correlation
  • angular distribution: anisotropy
  • background
  • CMS
  • p nucleus: scattering
  • lead