Two Ridges, One Explanation

TL;DR

This paper explains the 'ridge' phenomenon in high-energy collisions as a result of initial state correlations from Color Glass Condensate flux tubes combined with radial flow, unifying the soft and hard ridge observations.

Contribution

It proposes a unified explanation for the soft and hard ridge phenomena based on initial state correlations and radial flow, advancing understanding of their common origin.

Findings

The model reproduces the amplitude and azimuthal width of the soft ridge.

Nearly explains the amplitude of the hard ridge.

Suggests the soft and hard ridge are essentially the same phenomenon.

Abstract

We attribute the phenomenon known as "the ridge" to long range initial state correlations from Color Glass Condensate flux tubes and later stage radial flow. We show that this description can explain the amplitude and azimuthal width of the soft ridge and nearly explain that of the hard ridge, suggesting that the two are essentially the same phenomenon.