Speaker
Description
The neutrino fog represents a fundamental irreducible sensitivity limit for dark matter direct detection arising from coherent elastic neutrino-nucleus scattering (CEvNS). We present a precision calculation of the neutrino fog for spin-independent (SI), spin-dependent proton-coupled (SDp), and spin-dependent neutron-coupled (SDn) WIMP interactions on a natural xenon target, derived by matching a relativistic effective field theory of WIMP interactions with quarks onto nucleon-level effective couplings at the hadronic scale, which are subsequently expressed in terms of a complete basis of Galilean-invariant non-relativistic effective operators governing the WIMP-nucleus interaction at the nuclear scale. Nuclear shell-model response functions replace the Helm form factor approximation for both the WIMP signal and the CEvNS neutrino background, yielding spectral differences that induce a systematic rescaling of the fog boundary for WIMP masses above 50 GeV across all three interaction channels. Steep vertical drops in the fog are observed in the 10–100 GeV mass range, whose origin is investigated in terms of kinematic degeneracy between the atmospheric neutrino background and the WIMP recoil spectrum.