Modifications to Di-Jet Hadron Pair Correlations in Au+Au Collisions at sqrt(s_NN) = 200 GeV

Abstract

Azimuthal correlations of high-pT charged hadron pairs from (di-)jet-fragmentation are studied at mid-rapidity in Au+Au collisions at vsNN=200 GeV. The distribution of jet-associated partner hadrons (1.0< pT <2.5 GeV/c) per trigger hadron (2.5< pT <4.0 GeV/c) is found to vary with collision centrality, both in shape and in yield, indicating a significant effect of the nuclear collision medium on the (di-)jet fragmentation process.

Figures (3)

• Figure 1: Correlation functions, $C(\Delta\phi)$, for pairs of charged hadrons with 2.5 GeV/$c$$<p_{T}^{A}<$4.0 GeV/$c$$$ and 1.0 GeV/$c$$<p_{T}^{B}<$2.5 GeV/$c$$$ in different bins of collision centrality. The solid bands indicate the estimate of the background pair component (see text) within one unit of its systematic error.
• Figure 2: Jet-pair distributions $dN^{AB}_{\rm (Di-)Jet}/d(\Delta\phi)$ for different centralities, normalized per trigger particle. The shaded bands indicate the systematic error associated with the determination of $\Delta\phi_{Min}$. The dashed (solid) curves are the distributions that would result from increasing (decreasing) $\langle v_{2}^{A} v_{2}^{B} \rangle$ by one unit of the systematic error; the dotted curve would result from decreasing by two units.
• Figure 3: (a) Associated yields for near- and away-side peaks in the jet pair distribution, and (b) widths (RMS) of the peaks in the full 0--$2\pi$ distributions; plotted versus the mean number of participating nucleons for each event sample. Triangles show results from 0--20% central d+Au collisions at the same $\sqrt{s_{_{NN}}}$ppg039. Bars show statistical errors, shaded bands systematic.