Terrestrial and Solar Limits on Long-Lived Particles in a Dark Sector

Understand

Dark matter charged under a new gauge sector, as motivated by recent data, suggests a rich GeV-scale "dark sector" weakly coupled to the Standard Model by gauge kinetic mixing.

• The new gauge bosons can decay to Standard Model leptons, but this mode is suppressed if decays into lighter dark sector particles are kinematically allowed.
• These particles in turn typically have macroscopic decay lifetimes that are constrained by two classes of experiments, which we discuss.
• Lifetimes of 10 cm < c tau < 10^8 cm are constrained by existing terrestrial beam-dump experiments.