Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter

TL;DR

This paper investigates how dihadron correlations in Au+Au collisions at 200 GeV reveal jet quenching effects and medium response, showing shape evolution and spectral changes with collision centrality and particle momentum.

Contribution

It provides detailed analysis of azimuthal correlations and identifies distinct regions indicating jet suppression and medium response, advancing understanding of partonic matter behavior.

Findings

Away-side correlation shape evolves with p_T from broad to concave to convex.

The 'head' region shows softening spectra in central collisions, indicating jet quenching.

The 'shoulder' region's spectral slope remains constant across centralities, suggesting medium response mechanisms.

Abstract

Azimuthal angle \Delta\phi correlations are presented for charged hadrons from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing p_T, the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed "head" region centered at Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi +/- 1.1. The p_T spectrum for the "head" region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the "shoulder" region is independent of centrality and trigger p_T, which offers constraints on energy transport mechanisms and suggests that the "shoulder" region contains the medium response to energetic jets.