CMS logoCMS event Hgg
Compact Muon Solenoid
LHC, CERN

CMS-QCD-10-002 ; CERN-PH-EP-2010-031
Observation of Long-Range, Near-Side Angular Correlations in Proton-Proton Collisions at the LHC
J. High Energy Phys. 09 (2010) 091
Abstract: Results on two-particle angular correlations for charged particles emitted in proton-proton collisions at center-of-mass energies of 0.9, 2.36, and 7 TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (eta) and azimuthal angle ($\phi$). Short-range correlations in $\Delta\eta$, which are studied in minimum bias events, are characterized using a simple "independent cluster" parametrization in order to quantify their strength (cluster size) and their extent in $\eta$ (cluster decay width). Long-range azimuthal correlations are studied differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 inverse nb data set at 7 TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate transverse momentum of 1-3 GeV/c, 2.0 < |$\Delta\eta$| < 4.8 and $\Delta\phi \approx 0$. This is the first observation of such a long-range, near-side feature in two-particle correlation functions in $pp$ or $p\overline{p}$ collisions.
Figures CMS Publications
Figures

png pdf
Figure 1:

png pdf
Figure 2:

png pdf
Figure 3:

png pdf
Figure 4:

png pdf
Figure 5:

png pdf
Figure 6:

png pdf
Figure 7:

png pdf
Figure 8:

png pdf
Figure 9:

png pdf
Figure 10:
Compact Muon Solenoid
LHC, CERN