Sensitivity to decays of long-lived dark photons at the ILC (A Snowmass White Paper)

Abstract

We investigate the sensitivity to long-lived dark photons produced in Higgstrahlung events via the Higgs portal, $H\to {\gamma }_D{\gamma }_D$, with the Silicon Detector (SiD) at the International Linear Collider (ILC). These events provide a useful benchmark for tracking and vertex detector performance with long-lived particle decays at displaced vertices. The ILC is one of several Higgs factories proposed by the international community to study the properties of the Higgs boson at high precision.

Comments: Expanded discussion of backgrounds, additional figures and tables