Effective field theory interactions for liquid argon target in DarkSide-50 experiment

We reanalyze data collected with the DarkSide-50 experiment and recently used to set limits on the spin-independent interaction rate of weakly interacting massive particles (WIMPs) on argon nuclei with an effective field theory framework. The dataset corresponds to a total (16660±270)  kg d exposure using a target of low-radioactivity argon extracted from underground sources. We obtain upper limits on the effective couplings of the 12 leading operators in the nonrelativistic systematic expansion. For each effective coupling we set constraints on WIMP-nucleon cross sections, setting upper limits between 2.4×10-45  cm2 and 2.3×10-42  cm2 (8.9×10-45  cm2 and 6.0×10-42  cm2) for WIMPs of mass of 100  GeV/c2 (1000  GeV/c2) at 90% confidence level.