Ridge and Transverse Correlation at Separated Rapidities

TL;DR

This paper proposes a phenomenological model linking ridge and single-particle distributions in heavy-ion collisions, suggesting that transverse correlations driven by semihard partons explain the observed ridge structure without requiring long-range longitudinal correlations.

Contribution

It introduces a new interpretation of the ridge phenomenon based on transverse correlations and initial state uncertainties, challenging the need for long-range longitudinal correlations.

Findings

The ridge distribution correlates with the single-particle distribution in pseudorapidity.

Transverse correlations stimulated by semihard partons can explain the ridge structure.

No evidence for long-range longitudinal correlations was found.

Abstract

A simple phenomenological relationship between the ridge distribution in $\Delta\eta$ and the single-particle distribution in $\eta$ can be established from the PHOBOS data on both distributions. The implication points to the possibility that there is no long-range longitudinal correlation. An interpretation of the relationship is then developed, based on the recognition that longitudinal uncertainty of the initial configuration allows for non-Hubble-like expansion at early time. It is shown that the main features of the ridge structure can be explained in a model where transverse correlation stimulated by semihard partons is the principal mechanism.