# Automating the Construction of Jet Observables with Machine Learning

## TL;DR

This paper presents a machine learning-based method to automatically construct simple, analytic jet observables that fully describe M-body phase space, improving particle classification tasks in high-energy physics.

## Contribution

It introduces a novel automated procedure for building jet observables that specify M-body phase space, enabling tailored and more effective particle tagging.

## Key findings

- Validated on distinguishing H→bb̄ from g→bb̄ with M=3.
- Designed observables for boosted Z' search with M=4.
- Outperformed standard 2-prong tagging methods.

## Abstract

Machine-learning assisted jet substructure tagging techniques have the potential to significantly improve searches for new particles and Standard Model measurements in hadronic final states. Techniques with simple analytic forms are particularly useful for establishing robustness and gaining physical insight. We introduce a procedure to automate the construction of a large class of observables that are chosen to completely specify $M$-body phase space. The procedure is validated on the task of distinguishing $H\rightarrow b\bar{b}$ from $g\rightarrow b\bar{b}$, where $M=3$ and previous brute-force approaches to construct an optimal product observable for the $M$-body phase space have established the baseline performance. We then use the new method to design tailored observables for the boosted $Z'$ search, where $M=4$ and brute-force methods are intractable. The new classifiers outperform standard $2$-prong tagging observables, illustrating the power of the new optimization method for improving searches and measurement at the LHC and beyond.