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With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the Majorana Demonstrator enable searches for several classes of exotic dark matter (DM) models. In this work, we report new experimental limits on keV-scale sterile neutrino DM via the transition magnetic moment from conversion to active neutrinos 𝜈𝑠→𝜈𝑎. We report new limits on fermionic dark matter absorption (𝜒+𝐴→𝜈+𝐴) and sub-GeV DM-nucleus 3→2 scattering (𝜒+𝜒+𝐴→𝜙+𝐴), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). These searches utilize the (1–100)-keV low-energy region of a 37.5-kg y exposure collected by the Demonstrator between May 2016 and November 2019 using a set of 76Ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation.
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Even lighter particle dark matter
We report on recent progress in the search for dark matter particleswith masses from 1 Mev c ^{-2} − 2 to 1 Gev c ^{-2} − 2 .Several dark matter candidates in this mass range are expected togenerate measurable electronic-recoil signals in direct-detectionexperiments. We focus on dark matter particles scattering with electronsin semiconductor detectors since they have fundamentally the highestsensitivity due to their low ionization threshold. Charge-coupled device(CCD) silicon detectors are the leading technology, with significantprogress expected in the coming years. We present the status of the CCDprogram and briefly report on other efforts.
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- Award ID(s):
- 2110585
- PAR ID:
- 10439078
- Publisher / Repository:
- SciPost
- Date Published:
- Journal Name:
- SciPost Physics Proceedings
- Issue:
- 12
- ISSN:
- 2666-4003
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.21468/SciPostPhysProc.12.001
