The Monte Carlo Ecosystem in High-Energy Physics: A Primer

TL;DR

This paper provides a comprehensive, structured overview of the Monte Carlo ecosystem in high-energy physics, focusing on event generators, their methodologies, and their role in collider workflows, aimed at early-stage researchers.

Contribution

It offers an up-to-date, organized primer on the conceptual and technical aspects of Monte Carlo event generators in collider physics, emphasizing interoperability and future challenges.

Findings

Clarifies the architecture and methodology of Monte Carlo event generators.

Highlights challenges in large-scale simulations and interoperability.

Discusses future sustainability and computing landscape impacts.

Abstract

Monte Carlo event generators are the central interface between theoretical calculations and experimental measurements in collider physics. Over several decades, a comprehensive and highly modular ecosystem of tools has developed around them, encompassing matrix-element calculations, parton showers, hadronisation models, and their integration with detector simulation, event-level analysis and statistical inference. While these tools are ubiquitous in modern research, the conceptual scope and technical structure of the full simulation chain can be challenging to navigate, particularly for researchers entering the field. In this primer, we provide a structured and up-to-date overview of the high-energy physics Monte Carlo ecosystem, focusing primarily on event-generator methodologies and their role within the broader collider workflow. We discuss the conceptual foundations of modern generators, the computational and organisational challenges of large-scale simulations, and the principles that enable interoperability and reproducibility across theory and experiment. We also examine the evolving computing landscape and sustainability considerations that will shape the future development of these tools. Aimed primarily at early-stage doctoral researchers while serving as a reference for the broader community, this article seeks to clarify architecture, methodology, and long-term trajectory of Monte Carlo event generation in collider physics.