Nuclear-recoil quenching factor ($Q(E)=Y_{\mathrm{nuclear}}(E)/Y_{\mathrm{electron}}(E)$)

The relative light or charge yield of a nuclear recoil compared with an electron recoil at the same deposited energy in a specified material and field configuration. It connects an electron-equivalent calibration scale with a recoil-energy scale. It can depend on energy and measurement conditions; assuming a constant or extrapolating below calibration changes light-WIMP interpretations. It does not mean energy conservation fails: energy can enter channels not measured by that readout.