CMS: Observation of long-range, near-side angular correlations in proton-proton collisions at the LHC

Authors

S. Chatrchyan
Ekaterina Avdeeva, University of Nebraska-LincolnFollow
Kenneth Bloom, University of Nebraska-LincolnFollow
S. Bose, University of Nebraska - LincolnFollow
Jamila Butt, University of Nebraska - Lincoln
Daniel R. Claes, University of Nebraska-LincolnFollow
Aaron Dominguez, University of Nebraska-LincolnFollow
M. Eads, University of Nebraska-Lincoln, Lincoln,Follow
R. Gonzalez Suarez, University of Nebraska - Lincoln
P. Jindal, University of Nebraska - Lincoln
J. Keller, University of Nebraska - LincolnFollow
D. Knowlton, University of Nebraska-LincolnFollow
Ilya Kravchenko, University of Nebraska-LincolnFollow
Jose Lazo-Flores, University of Nebraska-LincolnFollow
Helena Malbouisson, University of Nebraska - Lincoln
Sudhir Malik, University of Nebraska - LincolnFollow
F. Meier, University of Nebraska-Lincoln, Lincoln,Follow
Gregory Snow, University of Nebraska - LincolnFollow

Date of this Version

2010

Citation

JHEP09 (2010) 091

Comments

Open access

doi:10.1007/JHEP09(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 7TeV are presented, using data collected with the CMS detector over a broad range of pseudorapidity (n) and azimuthal angle (?). Short-range correlations in [?]n, 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 n (cluster decay width). Long-range azimuthal correlations are studied differentially as a function of charged particle multiplicity and particle transverse momentum using a 980 nb^-1 data set at 7TeV. In high multiplicity events, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate p_T of 1-3 GeV/c, 2.0 < |[?]n| < 4.8 and [?][?] [?]0. This is the first observation of such a long-range, near-side feature in two-particle correlation functions in pp or pp collisions.