MeV-scale dark matter deep underground

Abstract

We demonstrate that current and planned underground neutrino experiments could offer a powerful probe of few-MeV dark matter when combined with a nearby high-intensity low-to-medium energy electron accelerator. This experimental setup, an underground beam-dump experiment, is capable of decisively testing the thermal freeze-out mechanism for several natural dark matter scenarios in this mass range. We present the sensitivity reach in terms of the mass-coupling parameter space of existing and planned detectors, such as Super-K, SNO+, and JUNO, in conjunction with a hypothetical 100 MeV energy accelerator. This setup can also greatly extend the sensitivity of direct searches for new light weakly-coupled force-carriers independently of their connection to dark matter.

Discovering inelastic thermal relic dark matter at colliders

“…For smaller splittings and DM masses below a few GeV, we find that monophoton + missing momentum searches at Belle II could provide complementary sensitivity in this regime [96]. Finally, we comment that significant strong sensitivity could be achieved for m DM few GeV and small splittings with new electron beam-dump and active-target experiments [61,67,97,120,121], proposed proton-beam fixed target experiments [122][123][124], and future direct detection experiments [3] optimized for low threshold sensitivity. In this Appendix, we summarize the relevant cross sections and rates for the thermal relic abundances computed in Sec.…”

MeV dark matter complementarity and the dark photon portal

“…Dark matter at the MeV scale is an interesting possibility, offering a rich phenomenology [4]. The topic has witnessed increasing interest in light of null results in the search for WIMPs [17] and of the many upcoming experimental probes for MeV-scale dark matter [18][19][20][21][22][23]. Several MeV dark matter studies have been conducted in the literature, e.g.…”

Testing GeV-scale dark matter with fixed-target missing momentum experiments

“…Such sectors remain weakly constrained experimentally, though they have been studied in many contexts -for example to address anomalies in dark matter direct and indirect detection [62][63][64][65][66], resolve puzzles in simulations of structure formation [67,68], modify the number of relativistic species in the early universe [69,70], explain the "cosmological coincidence" between dark and visible energy-densities [17,18], resolve the proton charge radius and other SM anomalies [71][72][73][74][75], and explore novel hidden-sector phenomenology [25,64,69,.…”