Cosmic-ray detector might have spotted nuggets of dark matter



-->Scanning the sky: the Middle Drum facility of the Telescope Array observatory in the Utah desert. Could anomalous signals seen by the observatory be evidence for axion quark nuggets?
(Courtesy: Ben Stokes/University of Utah)

A series of mysterious events recorded by a cosmic-ray observatory a decade ago could be the signature of an unusual form of dark matter called “axion quark nuggets” – according to Ariel Zhitnitsky of the University of British Columbia in Canada. These nuggets are hypothetical bundles of antiquarks (or quarks) wrapped inside a layer of axions