Dark-matter direct detection: WIMP nuclear recoil, rate R ∝ ρ_χ·σ·⟨v⟩/m_χ

WIMPs from the galactic halo (local density ρ_χ ≈ 0.3-0.4 GeV/cm³, v̄ ≈ 220 km/s Maxwell-Boltzmann) scatter elastically off target nuclei in a shielded underground detector, depositing keV-scale nuclear recoils detected via scintillation +…