Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Measurement of Jet Modification at RHIC

Fuqiang Wang

TL;DR

At RHIC, high-pT hadron yields in central Au+Au relative to p+p are suppressed and back-to-back jet correlations are weakened, while d+Au resembles p+p, consistent with final-state parton energy loss in the medium (jet quenching). The authors attempt a statistical reconstruction of jets in the large STAR TPC by background subtraction, event mixing, and elliptic flow corrections, using a large-pT trigger (4–6 GeV/c) and associated hadrons (0.15–4 GeV/c). They report that central Au+Au events correspond to higher energy jets selected by the trigger, with near- and away-side correlations showing increased multiplicity and total transverse momentum, and the away side being softened compared with p+p. This supports jet modification in heavy-ion collisions at RHIC and provides experimental access to medium density and energy-loss mechanisms.

Abstract

Charged hadrons (0.15 < pt < 4 GeV/c) associated with a large pt trigger particle (4 < pt < 6 GeV/c) are statistically reconstructed in the large acceptance STAR TPC for p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. Preliminary results on transverse momentum distributions of these hadrons are presented, separately on the near and away side from the trigger particle. An increase in the multiplicity and total scalar pt of these hadrons from p+p to central Au+Au collisions is observed. The away side distribution is found to be significantly softened in central Au+Au with respect to p+p collisions. The results are consistent with modification of jets in heavy ion collisions at RHIC.

Measurement of Jet Modification at RHIC

TL;DR

At RHIC, high-pT hadron yields in central Au+Au relative to p+p are suppressed and back-to-back jet correlations are weakened, while d+Au resembles p+p, consistent with final-state parton energy loss in the medium (jet quenching). The authors attempt a statistical reconstruction of jets in the large STAR TPC by background subtraction, event mixing, and elliptic flow corrections, using a large-pT trigger (4–6 GeV/c) and associated hadrons (0.15–4 GeV/c). They report that central Au+Au events correspond to higher energy jets selected by the trigger, with near- and away-side correlations showing increased multiplicity and total transverse momentum, and the away side being softened compared with p+p. This supports jet modification in heavy-ion collisions at RHIC and provides experimental access to medium density and energy-loss mechanisms.

Abstract

Charged hadrons (0.15 < pt < 4 GeV/c) associated with a large pt trigger particle (4 < pt < 6 GeV/c) are statistically reconstructed in the large acceptance STAR TPC for p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. Preliminary results on transverse momentum distributions of these hadrons are presented, separately on the near and away side from the trigger particle. An increase in the multiplicity and total scalar pt of these hadrons from p+p to central Au+Au collisions is observed. The away side distribution is found to be significantly softened in central Au+Au with respect to p+p collisions. The results are consistent with modification of jets in heavy ion collisions at RHIC.

Paper Structure

This paper contains 2 sections, 3 figures.

Table of Contents

  1. Data Analaysis
  2. Results

Figures (3)

  • Figure 1: The per trigger particle normalized $\Delta\phi$ distributions for p+p (a) and 5% most central Au+Au collisions (b). See text for explanation of the curves.
  • Figure 2: Charged hadron multiplicity (a) and total scalar $p_{\perp}$ (b) on the near and away side in p+p (open symbols) and Au+Au collisions. Shown in caps are systematic errors.
  • Figure :