WIMP Dark Matter Search using a 3. 1 tonne year Exposure of the XENONnT Experiment

We report on a search for weakly interacting massive particle (WIMP) dark matter (DM) via elastic DM-xenon-nucleus interactions in the XENONnT experiment. We combine datasets from the first and second science campaigns resulting in a total exposure of 3. 1\;tonne. In a blind analysis of nuclear recoil events with energies above 3. 8\, keV₍ₑ, we find no significant excess above background. We set new upper limits on the spin-independent WIMP-nucleon scattering cross-section for WIMP masses above 10\, GeV/c² with a minimum of 1. 7\, \, 10^-47\, cm² at 90\, \% confidence level for a WIMP mass of 30\, GeV/c². We achieve a best median sensitivity of 1. 4\, \, 10^-47\, cm² for a 41\, GeV/c² WIMP. Compared to the result from the first XENONnT science dataset, we improve our sensitivity by a factor of up to 1. 8.