The Rise and Fall of the Ridge

Recent data from Au+Au collisions at RHIC show unexpectedly large near-angle correlations that broaden longitudinally with centrality. It's been shown that for both 62.4 GeV and 200 GeV collisions, the amplitude of this ridge-like correlation rises rapidly with centrality, reaches a maximum, and then falls in the most central collisions. In this talk we explain how the rise and fall of the ridge can be easily understood in a picture where final momentum-space correlations are driven by initial coordinate space density fluctuations. We devise a model based on $v_n$ fluctuations from participant eccentricity fluctuations and use multiplicity and $v_2$ measurements from ALICE to predict the amplitude of the ridge at the LHC.