High p_T Triggered Delta-eta,Delta-phi Correlations over a Broad Range in Delta-eta

TL;DR

This paper presents the first comprehensive measurement of high p_T triggered particle correlations over a broad pseudorapidity range in Au+Au collisions, revealing the longitudinal extent of the ridge structure and its dependence on collision centrality.

Contribution

It provides the first detailed measurement of pseudorapidity and azimuthal correlations over a wide range, extending understanding of the ridge phenomenon in heavy-ion collisions.

Findings

The ridge persists up to Delta-eta=4 in central collisions.

The ridge diminishes with decreasing centrality and disappears around Npart=80.

Correlation structures vary with collision centrality and pseudorapidity.

Abstract

The first measurement of pseudorapidity (Delta-eta) and azimuthal angle (Delta-phi) correlations between high transverse momentum charged hadrons (p_T > 2.5 GeV/c) and all associated particles is presented at both short- (small Delta-eta) and long-range (large Delta-eta) over a continuous pseudorapidity acceptance (-4<Delta-eta<2). In these proceedings, the various near- and away-side features of the correlation structure are discussed as a function of centrality in Au+Au collisions measured by PHOBOS at sqrt(s_NN)=200 GeV. In particular, this measurement allows a much more complete determination of the longitudinal extent of the ridge structure, first observed by the STAR collaboration over a limited eta range. In central collisions the ridge persists to at least Delta-eta=4, diminishing in magnitude as collisions become more peripheral until it disappears around Npart=80.