DarkSide-50 532-day dark matter search with low-radioactivity argon

The DarkSide-50 direct-detection dark matter experiment is a dual-phase argon time projection chamber operating at Laboratori Nazionali del Gran Sasso. This paper reports on the blind analysis of a (16 660±270) kg d exposure using a target of low-radioactivity argon extracted from underground sources. We find no events in the dark matter selection box and set a 90% C.L. upper limit on the dark matter--nucleon spin-independent cross section of 1.14×10^-44 cm² (3.78×10^-44 cm², 3.43×10^-43 cm²) for a WIMP mass of 100 GeV/c² (1 TeV/c², 10 TeV/c²).