Jet Modification in Heavy Ion Collisions at RHIC

TL;DR

This paper reviews key findings on jet modifications in heavy ion collisions at RHIC, highlighting suppression effects, new gamma-jet measurements, and novel correlation structures indicating complex medium interactions.

Contribution

It provides the first results from gamma-jet events and discusses new observed structures in di-hadron correlations in heavy ion collisions.

Findings

Suppression of high- extit{p}_T{} hadron yields due to parton energy loss

Observation of a long-range ridge structure in di-hadron correlations

Broadening of recoil jets indicating medium effects

Abstract

These proceedings present a brief overview of the main results on jet-modifications in heavy ion collisions at RHIC. In heavy ion collisions, jets are studied using single hadron spectra and di-hadron correlations with a high-\pt{} trigger hadrons. At high pt, a suppression of the yields due to parton energy loss is observed. A quantitative confrontation of the data with various theoretical approaches to energy loss in a dense QCD medium is being pursued. First results from $\gamma$-jet events, where the photon balances the initial jet energy, are also presented and compared to expectations from models based on di-hadron measurements. At intermediate pt, two striking modifications of the di-hadron correlation structure are found in heavy ion collisions: the presence of a long-range {\it ridge} structure in \deta{}, and a large broadening of the recoil jet. Both phenomena seem to indicate an interplay between hard and soft physics.