any of a family of mesons consisting of a charmed quark and a charmed antiquark.
an early name for the J/psi particle.
Origin of psi particle
First recorded in 1970–75
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See J/psi particle.
An electrically neutral meson having a mass 7,213 times that of the electron and a mean lifetime of approximately 1 X 10-20 seconds, composed, like the J/psi particle, of a charm-anticharm quark pair. See Table at subatomic particle.
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