In particle physics, the property or internal quantum number that is conserved in strong and electromagnetic interactions, but not in weak interactions (see strong force, electromagnetic force, weak force). Charmed particles contain at least one charmed quark; the charm number of these quarks is +1. Charmed antiquarks (see antimatter) have a charm number of 1. The first charmed particle was discovered in 1974.

This entry comes from Encyclopædia Britannica Concise.
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