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The Heavy Photon Search experiment took its first data in a 2015 engineeringrun at the Thomas Jefferson National Accelerator Facility, searching for aprompt, electro-produced dark photon with a mass between 19 and 81 MeV/$c^2$. Asearch for a resonance in the $e^{+}e^{-}$ invariant mass distribution, using1.7 days (1170 nb$^{-1}$) of data, showed no evidence of dark photon decaysabove the large QED background, confirming earlier searches and demonstratingthe full functionality of the experiment. Upper limits on the square of thecoupling of the dark photon to the Standard Model photon are set at the levelof 6$\times$10$^{-6}$. Future runs with higher luminosity will explore newterritory.

Search for a Dark Photon in Electro-Produced $e^{+}e^{-}$ Pairs with the Heavy Photon Search Experiment at JLab