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\,keVNR, 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.