Measurements of di-jets in p+p and Au+Au in the STAR experiment

TL;DR

This paper reports on measurements of di-jet production and jet-hadron correlations in proton-proton and gold-gold collisions at 200 GeV, providing insights into jet quenching and energy loss in the quark-gluon plasma.

Contribution

It introduces a comprehensive analysis of di-jet and jet-hadron correlations in heavy-ion collisions using the STAR detector, highlighting the effects of the medium on jet structure and energy.

Findings

Di-jet yields are suppressed in Au+Au compared to p+p.

Jet-hadron correlations show modifications consistent with energy loss.

Reconstructed di-jets help characterize the medium's impact on jet properties.

Abstract

Jets are produced from hard scatterings in the early stages of heavy-ion collisions. It is expected that these high-p$_T$ partons travel through the hot and dense medium before fragmenting. Therefore they are expected to suffer energy loss in the QGP via gluon radiation or elastic collisions along their path. Measurements from full jet reconstruction help in the understanding of energy loss and its effect{\ss} on the jet structure and energy profile. A data-driven characterization of the background in Au+Au is needed in order to compare the results to p+p. The large coverage of the STAR detector along with an online trigger also allows for reconstructing di-jets. Suitable selection of trigger jets allows for studying a subset of jets on the recoil side which are biased towards higher energy loss because of a larger, on average, in-medium path length traversed. Trigger jets are also used to study jet-hadron correlations as an independent measurement to assess the effect of energy loss on the recoil side. We present measurements of di-jets and jet-hadron correlations in the presence of reconstructed di-jets in Au+Au and p+p at 200 GeV in the STAR experiment.