Probing Light Dark Particles in Neutrino Scattering Experiments

In this work we investigate the production of a dark fermionic particle $\chi$ in the neutrino scattering experiments. In the framework of effective field theory, such process can be induced by the effective four-fermion interactions involving neutrinos, the dark particle $\chi$ and standard model particles. We perform a comprehensive analysis of all possible Lorentz structures, considering representative neutrino experiments with distinct neutrino sources and target particles. In particular, we examine the constraints on the effective couplings for the neutrino-nucleus scattering by the latest COHERENT CsI and CONUS+ data, as well as the prospects at the DUNE near detector from neutrino-electron scattering. It turns out the current COHERENT and CONUS+ constraints on the cutoff scales are less stringent than those from the existing Large Hadron Collider data and the SN1987A observations. However, the DUNE near detector could probe the cutoff scales beyond the existing CHARM II and LEP limits up to roughly 1 TeV, for the dark particle mass up to roughly 50 MeV. Our results demonstrate the complementarity between neutrino experiments and collider searches in probing the dark sector physics.