  The sensitivity to dark matter signals at neutrino experiments is
fundamentally challenged by the neutrino rates, as they leave similar
signatures in their detectors. As a way to improve the signal sensitivity, we
investigate a dark matter search strategy which utilizes the timing and energy
spectra to discriminate dark matter from neutrino signals at low-energy,
pulsed-beam neutrino experiments. This strategy was proposed in our companion
paper arXiv:1906.10745, which we apply to potential searches at COHERENT,
JSNS$^2$, and CCM. These experiments are not only sources of neutrinos but also
high intensity sources of photons. The dark matter candidate of interest comes
from the relatively prompt decay of a dark sector gauge boson which may replace
a Standard-Model photon, so the delayed neutrino events can be suppressed by
keeping prompt events only. Furthermore, prompt neutrino events can be rejected
by a cut in recoil energy spectra, as their incoming energy is relatively small
and bounded from above while dark matter may deposit a sizable energy beyond
it. We apply the search strategy of imposing a combination of energy and timing
cuts to the existing CsI data of the COHERENT experiment as a concrete example,
and report a mild excess beyond known backgrounds. We then investigate the
expected sensitivity reaches to dark matter signals in our benchmark
experiments.
