Geometry optimization for long-lived particle detectors

Abstract

The proposed designs of many auxiliary long-lived particle (LLP) detectors at the LHCcall for the instrumentation of a large surface area inside the detector volume,in order to reliably reconstruct tracks and LLP decay vertices.Taking the CODEX-b detector as an example,we provide a proof-of-concept optimization analysis that demonstratesthe required instrumented surface area can be substantially reduced for many LLP models, while only marginally affecting the LLP signal efficiency.This optimization permits a significant reduction in cost and installation time, and may also inform the installation order for modular detector elements.We derive a branch-and-bound based optimization algorithm that permits highly computationally efficient determination of optimal detector configurations,subject to any specified LLP vertex and track reconstruction requirements.We outline the features of a newly-developed generalized simulation framework,for the computation of LLP signal efficiencies across a range of LLP models and detector geometries.