U.S. Department of Energy

Pacific Northwest National Laboratory

Axions

A subatomic particle of low mass and energy that is postulated to exist by the Peccei-Quinn theory in 1977 because of certain properties of the strong force. The axion originally arose as part of an elegant solution to the “strong CP problem” (charge conjugation and parity) in the Standard Model of particle physics. It was then appreciated that a light axion is an ideal cold dark matter candidate.

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