Axial-vector neutral-current measurements in coherent elastic neutrino-nucleus scattering experiments

Coherent elastic neutrino-nucleus scattering ( CE ν NS ) is predominantly governed by vector neutral-current interactions, with subleading contributions arising from the axial current in nuclei with nonzero ground-state spin. Experimentally, the extraction of axial-current contributions has been so far of little interest, mainly because of the challenges its measurement entails. In this work, we investigate the relative size of the vector and axial components for target materials currently employed by the neutrino and dark matter experimental communities. We identify fluorine-based compounds as the most promising targets for probing the axial-current event rate. Among them, octafluoropropane ( C 3 F 8 ) emerges as a particularly suitable candidate, given its widespread use in spin-dependent dark matter searches and its relevance for upcoming dedicated CE ν NS experiments. Considering both pion decay-at-rest and reactor neutrino fluxes, we show that such measurements can allow an indirect determination of the axial coupling at the ∼ 10 % level, depending on flux uncertainties and detector thresholds. We further emphasize that measurements of the axial current will allow one to probe spin-dependent new physics scenarios through CE ν NS .