The Heavy Photon Search Experiment at Jefferson Laboratory

The Heavy Photon Search (HPS) is a new experiment at Jefferson Lab that will search for massive U(1) vector bosons (also known as heavy photons, dark photons, or $A'$) of mass 20--1000 MeV that couple to electric charge with relative coupling $\alpha'/\alpha$ of $10^{-5}$--$10^{-10}$. The HPS experiment is designed to produce heavy photons by electron scattering off a fixed target, and detect them using two decay channels ($e^+e^-$ or $\mu^+\mu^-$ pairs) and two signatures (invariant mass resonance and displaced decay vertex). The detector is a compact, large-acceptance forward spectrometer comprising a silicon microstrip tracker for momentum measurement and vertexing, an electromagnetic calorimeter for triggering on $e^+e^-$, and a muon detector for triggering on $\mu^+\mu^-$. This talk will cover the motivations for heavy photons and give an overview of the HPS experiment.