The Heavy Photon Search experiment took its first data in a 2015 engineering
run at the Thomas Jefferson National Accelerator Facility, searching for a
prompt, electro-produced dark photon with a mass between 19 and 81 MeV/$c^2$. A
search for a resonance in the $e^{+}e^{-}$ invariant mass distribution, using
1.7 days (1170 nb$^{-1}$) of data, showed no evidence of dark photon decays
above the large QED background, confirming earlier searches and demonstrating
the full functionality of the experiment. Upper limits on the square of the
coupling of the dark photon to the Standard Model photon are set at the level
of 6$\times$10$^{-6}$. Future runs with higher luminosity will explore new
territory.
