Correlation measurements indicate that excess two particle correlations
extend over causally disconnected rapidity ranges. Although, this enhancement
is broad in relative rapidity η=η1​−η2​, it is focused in a narrow
region in relative azimuthal angle ϕ=ϕ1​−ϕ2​. The resulting
structure looks like a ridge centered at η=ϕ=0. Similar ridge
structures are observed in correlations of particles associated with a jet
trigger (the hard ridge) and in correlations without a trigger (the soft
ridge). The long range rapidity behavior requires that the correlation
originates in the earliest stage of the collision, and probes properties of the
production mechanism. Glasma initial conditions as predicted by the theory of
Color Glass Condensate and provide a and early stage correlation that naturally
extends far in rapidity. We have previously shown that the soft ridge is a
consequence of particles forming from an initial Glasma phase that experience a
later stage transverse flow. We extend this work to study the ridge dependence
on the pt​ of the correlated pairs. We then determine the soft contribution
to the hard ridge.Comment: Proceeding of the APS meeting of the Division of Particles and Fields
2009, Detroit, Mi. Also see arXiv:0910.359