Measurements of jet structure and fragmentation from full jet reconstruction in heavy ion collisions at RHIC

TL;DR

This paper reports on measurements of fully reconstructed di-jets in heavy-ion collisions at RHIC, providing insights into jet structure modifications due to energy loss in hot QCD matter.

Contribution

It presents the first detailed comparison of jet fragmentation functions in p+p and Au+Au collisions at RHIC using full jet reconstruction.

Findings

Fragmentation functions are modified in Au+Au collisions.

Systematic uncertainties in the ratio of fragmentation functions are assessed.

Results shed light on jet quenching effects in hot QCD matter.

Abstract

Measurements of inclusive hadron suppression and di-hadron azimuthal correlations have provided important insights into jet quenching in hot QCD matter. However, they do not provide access to the energy of the hard scattering and are limited in their sensitivity since they can be affected by biases toward hard fragmentation and small energy loss. Full jet reconstruction in heavy-ion collisions enables a complete study of the modification of jet structure due to energy loss, but is challenging due to the high-multiplicity environment. We present measurements of fully reconstructed di-jets at mid-rapidity in 200 GeV p+p and central Au+Au collisions performed with the STAR detector. We compare fragmentation functions measured in 200 GeV p+p and central Au+Au collisions and assess the systematic uncertainties of their ratio.