Search for vector mediator of dark matter production in invisible decay mode

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Date
2018-04Type
- Journal Article
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Cited 82 times in
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Cited 90 times in
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Abstract
A search is performed for a new sub-GeV vector boson (A′) mediated production of dark matter (χ) in the fixed-target experiment, NA64, at the CERN SPS. The A′, called dark photon, can be generated in the reaction e−Z→e−ZA′ of 100 GeV electrons dumped against an active target followed by its prompt invisible decay A′→χ¯χ. The experimental signature of this process would be an event with an isolated electron and large missing energy in the detector. From the analysis of the data sample collected in 2016 corresponding to 4.3×1010 electrons on target no evidence of such a process has been found. New stringent constraints on the A′ mixing strength with photons, 10−5≲ε≲10−2, for the A′ mass range mA′≲1 GeV are derived. For models considering scalar and fermionic thermal dark matter interacting with the visible sector through the vector portal the 90% C.L. limits 10−11≲y≲10−6 on the dark-matter parameter y=ε2αD(mχmA′)4 are obtained for the dark coupling constant αD=0.5 and dark-matter masses 0.001≲mχ≲0.5 GeV. The lower limits αD≳10−3 for pseudo-Dirac dark matter in the mass region mχ≲0.05 GeV are more stringent than the corresponding bounds from beam dump experiments. The results are obtained by using exact tree level calculations of the A′ production cross sections, which turn out to be significantly smaller compared to the one obtained in the Weizsäcker-Williams approximation for the mass region mA′≳0.1 GeV. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000259369Publication status
publishedExternal links
Journal / series
Physical Review DVolume
Pages / Article No.
Publisher
American Physical Society (APS)Organisational unit
03503 - Rubbia, André / Rubbia, André
Funding
169133 - NA64 - Search for Dark Sectors in Missing Energy Events (SNF)
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Show all metadata
Citations
Cited 82 times in
Web of Science
Cited 90 times in
Scopus
ETH Bibliography
yes
Altmetrics