Searching for Ultralight Scalar Dark Matter with Muonium and Muonic Atoms.

Ultralight scalar dark matter may induce apparent oscillations of the muon mass, which may be directly probed via temporal shifts in the spectra of muonium and muonic atoms. Existing datasets and ongoing spectroscopy measurements with muonium are capable of probing scalar-muon interactions that are up to 12 orders of magnitude more stringent than astrophysical bounds. Ongoing free-fall experiments with muonium can probe forces associated with the exchange of virtual ultralight scalar bosons between muons and standard-model particles, offering up to 5 orders of magnitude improvement in sensitivity over complementary laboratory and astrophysical bounds.

Erratum: Probing Long-Range Neutrino-Mediated Forces with Atomic and Nuclear Spectroscopy [Phys. Rev. Lett. 120, 223202 (2018)].

This corrects the article DOI: 10.1103/PhysRevLett.120.

Direct limits on the interaction of antiprotons with axion-like dark matter.

Astrophysical observations indicate that there is roughly five times more dark matter in the Universe than ordinary baryonic matter, and an even larger amount of the Universe's energy content is attributed to dark energy. However, the microscopic properties of these dark components remain unknown. Moreover, even ordinary matter-which accounts for five per cent of the energy density of the Universe-has yet to be understood, given that the standard model of particle physics lacks any consistent explanation for the predominance of matter over antimatter.