Hunt for sub-GeV dark matter at neutrino facilities: A survey of past and present experiments

We survey the sensitivity of past and present neutrino experiments to MeV-GeV scale vector portal dark matter and find that these experiments possess novel sensitivity that has not yet fully explored. Taking ${\alpha }_D=0.1$ and a dark photon to dark matter mass ratio of three, the combined recast of previous analyses of Big European Bubble Chamber and a projection of $\mathrm{NO}\nu \mathrm{A}$’s sensitivity are found to rule out the scalar thermal target for dark matter masses between 10 and 100 MeV with existing data, while CHARM-II and $\mathrm{MINER}\nu \mathrm{A}$ place somewhat weaker limits. These limits can be improved by off-axis searches using the NuMI beam line and the MicroBooNE, MiniBooNE, or ICARUS detectors and can even begin to probe the Majorana thermal target. We conclude that past and present neutrino facilities can search for light dark matter concurrently with their neutrino program and reach a competitive sensitivity to proposed future experiments.

Figure 1

All limits and projections from existing fixed-target neutrino experiments. Limits based on existing data and analyses are given by solid lines, while projections are dotted.

Figure 2

We show a slice of the vector portal dark matter parameter space with ${\alpha }_D=0.1$ and $m_{A^{\prime }}=3m_{\chi }$. The solid (dotted) black lines show the parameter space for which a complex scalar (Majorana) dark matter candidate coupled to a DP reproduces the observed dark matter relic density. The blue shaded region is excluded by the $\mathrm{NO}\nu \mathrm{A}$ experiment, while the gray shaded region is excluded by a recast of a physics analysis of BEBC. The other dotted lines show the projected sensitivity of a new physics analysis of ${10}^{21}$ POT of data for MiniBooNE, ICARUS, and MicroBooNE taking data from the NuMI beam line. SBN is too far off axis to provide much sensitivity to vector portal dark matter produced by the NuMI beam line and is not shown.