Probing the Solar ^{8}B Neutrino Fog with XENONnT

We report a 3.3σ measurement of coherent elastic neutrino-nucleus scattering from solar ^{8}B neutrinos using a 6.77  t×yr exposure from the XENONnT experiment, inferring a solar ^{8}B neutrino flux of (5_{-2}^{+3})×10^{6}  cm^{-2} s^{-1}, consistent with previous measurements. In the presence of the ^{8}B "neutrino fog," we find no evidence for light dark matter, and observe diminishing returns in sensitivity with increasing exposure. A 93% increase in exposure from the previous search improves the median sensitivity to the nucleon scattering cross section for a 5  GeV/c^{2} spin-independent weakly interacting massive particle by 10%. The dataset was also used to measure the weak mixing angle at ∼0.02  GeV/c momentum transfer and constrain physics beyond the Standard Model.