  Among laboratory probes of dark matter, fixed-target neutrino experiments are
particularly well-suited to search for light weakly-coupled dark sectors. In
this paper, we show that the DAEdALUS source setup---an 800 MeV proton beam
impinging on a target of graphite and copper---can improve the present LSND
bound on dark photon models by an order of magnitude over much of the
accessible parameter space for light dark matter when paired with a suitable
neutrino detector such as LENA. Interestingly, both DAEdALUS and LSND are
sensitive to dark matter produced from off-shell dark photons. We show for the
first time that LSND can be competitive with searches for visible dark photon
decays, and that fixed-target experiments have sensitivity to a much larger
range of heavy dark photon masses than previously thought. We review the
mechanism for dark matter production and detection through a dark photon
mediator, discuss the beam-off and beam-on backgrounds, and present the
sensitivity in dark photon kinetic mixing for both the DAEdALUS/LENA setup and
LSND in both the on- and off-shell regimes.
