Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel
Abstract
We report the results of a search for a new vector boson (A) decaying into two dark matter particles χ1χ2 of different mass. The heavier χ2 particle subsequently decays to χ1 and an off-shell Dark Photon A∗ → e+e−. For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained reanalyzing the previous NA64 searches for an invisible decay A → χχ and axion-like or pseudo-scalar particles a → γ γ . With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for A masses from 2me up to 390 MeV and mixing parameter ε between 3 × 10−5 and 2 × 10−2. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000514581Publication status
publishedExternal links
Journal / series
The European Physical Journal CVolume
Pages / Article No.
Publisher
SpringerOrganisational unit
03503 - Rubbia, André / Rubbia, André
Funding
169133 - NA64 - Search for Dark Sectors in Missing Energy Events (SNF)
186181 - NA64 - Searching for Dark Sectors at the CERN SPS (SNF)
186158 - Development of Data Acquisition Systems based on Silicon Photomultipliers readouts to search for dark sectors in NA64 at CERN (SNF)
197346 - Study of Exotic Matter (SNF)
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