Absorption of fermionic dark matter by nuclear targets

Abstract

Absorption of fermionic dark matter leads to a range of distinct and novel signatures at dark matter direct detection and neutrino experiments. We study the possible signals from fermionic absorption by nuclear targets, which we divide into two classes of four Fermi operators: neutral and charged current. In the neutral current signal, dark matter is absorbed by a target nucleus and a neutrino is emitted. This results in a characteristically different nuclear recoil energy spectrum from that of elastic scattering. The charged current channel leads to induced β decays in isotopes which are stable in vacuum as well as shifts of the kinematic endpoint of β spectra in unstable isotopes. To confirm the possibility of observing these signals in light of other constraints, we introduce UV completions of example higher dimensional operators that lead to fermionic absorption signals and study their phenomenology. Most prominently, dark matter which exhibits fermionic absorption signals is necessarily unstable leading to stringent bounds from indirect detection searches. Nevertheless, we find a large viable parameter space in which dark matter is sufficiently long lived and detectable in current and future experiments.

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

“…For example, SENSEI can discover or exclude the scalar thermal target for DM masses below 100 MeV [2] in the near future, and Refs. [55,56] [57]. Furthermore, for the minimal DP model considered here, a complex scalar lighter than 6.9 MeV is ruled out [58] by the Planck measurement of N eff [41].…”

Direct detection and complementary constraints for sub-GeV dark matter

“…Significant interest, both from the experimental and theoretical perspective, has thus turned to the possibility of DM particle masses below the GeV -TeV range. Conventional direct detection experiments are essentially insensitive to such light particles -except for very large scattering cross sections, where cosmic rays can upscatter DM to relativistic energies [28] -but new methods and concepts are being developed to overcome these difficulties [29][30][31][32][33][34].…”

A study of New Physics searches with tritium and similar molecules

“…We are rather expecting a further suppression, for instance due to small mix-ing factors in the case of sterile neutrinos. Evaluating the box diagram, we derive the effective low-energy potential (3) (r). (27) The size of this effect is of O(10 −11 cm −1 ) and, hence, far below the current experimental sensitivity.…”

“…There is, however, observational evidence of physics not covered in the Standard Model. In the context of Dark Matter, for example, the interest to search for new sub-GeV particles has recently gained impetus [1][2][3], where molecules have been identified as good study objects [4]. In particular, molecular spectroscopy is one possibility to look for new dark forces [5,6].…”