How high is the neutrino floor?
  In this paper, we compute the contribution to the coherent elastic
neutrino-nucleus scattering cross section from new physics models in the
neutrino sector. We use this information to calculate the maximum value of the
so-called neutrino floor for direct dark matter detection experiments, which
determines when these detectors are sensitive to the neutrino background. After
including all relevant experimental constraints in different simplified
neutrino models, we have found that the neutrino floor can increase by various
orders of magnitude in the region of dark matter masses below 10 GeV in the
case of scalar mediators, however, this spectacular enhancement is subject to
the re-examination of supernovae bounds. The increase is approximately a factor
of two for vector mediators. In the light of these results, future claims by
direct detection experiments exploring the low-mass window must be carefully
examined if a signal is found well above the expected Standard Model neutrino
floor.
