Results on low-mass weakly interacting massive particles from a 11 kg-day target exposure of DAMIC at SNOLAB
We present constraints on the existence of weakly interacting massive particles (WIMPs) from a 11 kg-day target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies $$>$$200 eV$$_{\rm ee}$$ in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50 eV$$_{\rm ee}$$. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections $$\sigma_{\chi-n}$$ as low as $$3\times 10^{-41}$$ cm$^2$ for WIMPs with masses $$m_{\chi}$$ from 7 to 10 GeV$$c^{-2}$$ . These results are the strongest constraints from a silicon target on the existence of WIMPs with $$m_{\chi}$$$$<$9 GeV$$c^{-2}$$ and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- DAMIC
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1659450
- Report Number(s):
- arXiv:2007.15622; FERMILAB-PUB-20-284-E; oai:inspirehep.net:1809457
- Journal Information:
- TBD, Journal Name: TBD
- Country of Publication:
- United States
- Language:
- English
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