Long-Lived Particles at Future Colliders

TL;DR

Future colliders offer promising opportunities to discover long-lived particles, which could address key questions in physics like neutrino masses and dark matter, despite detection challenges.

Contribution

This paper reviews the potential of future colliders to detect long-lived particles and discusses specific physics cases and preliminary studies for different collider types.

Findings

Long-lived particles are detectable with dedicated methods at future colliders.

Future colliders can explore new physics models related to dark matter and neutrino masses.

Different collider types provide complementary advantages for long-lived particle searches.

Abstract

Long-lived particles have significant enough lifetimes as to, when produced in collisions, leave a distinct signature in the detectors. Driven by increasingly higher energies, trigger and reconstruction algorithms at particle colliders are optimized for increasingly heavier particles, which in turn, tend to be short-lived. This makes searches for long-lived particles difficult, usually requiring dedicated methods and sometimes dedicated hardware top spot them. However, taking upon the challenge brings enormous potential, since new, long-lived particles feature in a variety of promising new physics models that could answer most of the open questions of the standard model, such as: neutrino masses, Dark Matter, or the matter-antimatter unbalance in the Universe. Currently, the international high energy physics community is planning future facilities post-LHC, and various particle colliders have been proposed. Crucial physics cases connected to long-lived particles will be accessible then, and in this presentation, three interesting examples are highlighted: Heavy Neutral Leptons, Hidden Sectors connected to Dark Matter, and exotic Higgs boson decays. This is followed by a small review of the preliminary studies assuming different future colliders, exploiting the complementary advantages that different colliding particles and accelerator types provide.