The role of initial state radiation in quenched jets

TL;DR

This paper investigates how initial state radiation affects jet sub-structure measurements in proton-proton and heavy ion collisions, highlighting its significance for interpreting jet quenching data.

Contribution

It extends the JEWEL simulation to quantify the impact of initial state radiation on various jet observables in different collision systems.

Findings

Initial state radiation can significantly influence jet observables depending on the observable and jet radius.

The study provides insights into when initial state effects are sizable and must be considered.

Results help improve the interpretation of jet quenching measurements in heavy ion collisions.

Abstract

Jet quenching in heavy ion collisions and in particular the sub-structure of quenched jets are promising tools for investigating the microscopic processes underlying jet quenching and the background medium's response to energy and momentum depositions. A quantitative understanding of the data can, however, be complicated by the presence of initial state radiation in reconstructed jets. Using an extended version of JEWEL the effect of initial state radiation on different jet observables is studied in proton-proton and heavy ion collisions. It is shown that, depending on the observable and the jet radius, the initial state contributions can be sizable. Some general insights into when sizable effects can be expected also emerges.