HECATE: A long lived particle detector concept for the FCC-ee or CEPC

TL;DR

The paper proposes a detector concept called HECATE for future lepton colliders like FCC-ee and CEPC, utilizing larger caverns designed for hadron colliders to enhance searches for long-lived particles.

Contribution

It introduces a novel detector concept that leverages existing civil engineering plans to improve sensitivity to long-lived particles at future lepton colliders.

Findings

Potential to improve sensitivity to heavy neutral leptons by nearly half an order of magnitude.

Utilizes extra cavern space intended for hadron colliders for long-lived particle detection.

Demonstrates feasibility of integrating additional instrumentation without major civil engineering changes.

Abstract

The next generation of circular high energy collider is expected to be a lepton collider, FCC-ee at CERN or CEPC in China. However, the civil engineering concepts foresee to equip these colliders with bigger detector caverns than one would need for a lepton collider, so that they can be used for a hadron collider that may be installed in the same tunnel without further civil engineering. This opens up the possibility to install extra instrumentation at the cavern walls to search for new long-lived particles at the lepton collider. We use the example of heavy neutral leptons to show that such an installation could improve the sensitivity to the squared mixing parameter by almost half an order of magnitude.