  The Heavy Photon Search (HPS) is a new experiment at Jefferson Lab that will
search for heavy U(1) vector bosons (heavy photons or dark photons) in the mass
range of 20 MeV/c$^2$ to 1 GeV/c$^2$. Dark photons in this mass range are
theoretically favorable and may mediate dark matter interactions. The dark
photon couples to electric charge through kinetic mixing with the photon,
allowing its production through a process analogous to bremsstrahlung
radiation. HPS will utilize this production mechanism to probe dark photons
with relative couplings of ${\epsilon}^2 = {\alpha}'/{\alpha}$ ~ $10^{-5}$ to
$10^{-10}$ and search for the $e^{+}e^{-}$ or $\mu^{+}\mu^{-}$ decay of the
dark photon via two signatures (invariant mass and displaced vertex). Using
Jefferson Lab's high luminosity electron beam along with a compact large
acceptance forward spectrometer consisting of a silicon vertex tracker, lead
tungstate electromagnetic calorimeter and a muon detector, HPS will access
hitherto unexplored regions in the mass/coupling space.
