Collider Searches for Long-Lived Particles Beyond the Standard Model

TL;DR

This paper reviews the theoretical motivations, experimental strategies, and results of collider searches for long-lived particles beyond the Standard Model, highlighting challenges and future opportunities in detecting these elusive particles.

Contribution

It provides a comprehensive overview of long-lived particle searches, including historical results and future prospects, emphasizing the importance of tailored detection methods.

Findings

Decades of LLP search results constrain BSM theories.

Experimental strategies are evolving to improve LLP detection.

Future experiments have significant potential to discover LLPs.

Abstract

Experimental tests of the Standard Model of particle physics (SM) find excellent agreement with its predictions. Since the original formation of the SM, experiments have provided little guidance regarding the explanations of phenomena outside the SM, such as the baryon asymmetry and dark matter. Nor have we understood the aesthetic and theoretical problems of the SM, despite years of searching for physics beyond the Standard Model (BSM) at particle colliders. Some BSM particles can be produced at colliders yet evade being discovered, if the reconstruction and analysis procedures not matched to characteristics of the particle. An example is particles with large lifetimes. As interest in searches for such long-lived particles (LLPs) grows rapidly, a review of the topic is presented in this article. The broad range of theoretical motivations for LLPs and the experimental strategies and methods employed to search for them are described. Results from decades of LLP searches are reviewed, as are opportunities for the next generation of searches at both existing and future experiments.