Validating a Machine Learning Approach to Identify Quenched Jets in Heavy-Ion Collisions

TL;DR

This paper presents a machine learning method using LSTM neural networks to identify quenched jets in heavy-ion collisions, validated with simulated data including detector effects.

Contribution

The study introduces a novel LSTM-based approach trained on jet substructure to accurately predict jet quenching levels, validated with realistic simulations.

Findings

LSTM predictions strongly correlate with true jet energy loss.

The method effectively identifies quenching effects in a realistic detector environment.

The approach distinguishes true quenching features using multiple jet observables.

Abstract

Jet quenching is a phenomenon in heavy-ion collisions arising from jet interactions with the quark-gluon plasma (QGP). Its study is complicated by the interplay of multiple physics processes that affect jet observables. In addition, detector effects may influence the results and must be accounted for when identifying quenched jets. We employ a Long Short-Term Memory (LSTM) neural network trained on jet substructure, incorporating parton shower history, to predict jet-by-jet quenching levels. Using photon-jet samples from the \textsc{Jewel} event generator, we show that the LSTM predictions strongly correlate with true jet energy loss. This validates that the model effectively learns the features of jet-QGP interaction. We simulate detector effects using \textsc{Delphes} simulation framework and demonstrate that the method identifies quenching effects in a realistic environment. We test the approach with photon-jet momentum imbalance, jet fragmentation function, and jet shape, which were not included in the training, confirming its ability to distinguish true quenching features.