Measurements of charged dihadron DeltaEta-DeltaPhi correlations from the CMS
collaboration are presented for PbPb collisions at a center-of-mass energy of
2.76 TeV per nucleon pair over a broad range of pseudorapidity and the full
range of azimuthal angle. A significant correlated yield is observed for pairs
of particles with small DeltaPhi but large longitudinal separation DeltaEta,
commonly known as the "ridge". The ridge persists up to at least |DeltaEta| = 4
and the dependence of the ridge region shape and yield on collision centrality
and transverse momentum has been measured. A Fourier analysis of the long-range
two-particle correlation is presented and discussed in the context of higher
order flow coefficients.Comment: Proceedings of presentation given at Quark Matter 201
