  The sensitivity of direct detection of dark matter (DM) approaches the
so-called neutrino floor below which it is hard to disentangle the DM candidate
from the background neutrino. In this work we consider the scenario that no DM
signals are reported in various DM direct detection experiments and explore
whether the collider searches could probe the DM under the neutrino floor. We
adopt several simplified models in which the DM candidate couples only to
electroweak gauge bosons or leptons in the standard model through high
dimensional operators. After including the RGE running effect we investigate
constraints from direct detection, indirect detection and collider searches.
The collider search can probe a light DM below neutrino floor. Especially, for
the effective interaction of $\bar{\chi}\chi B_{\mu\nu}B^{\mu\nu}$, current
data of the mono-photon channel at the 13 TeV LHC has already covered entire
parameter space of the neutrino floor.
