Origin of D particle
First recorded in 1975–80
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Either of two subatomic particles in the meson family, one neutral and one positively charged, having masses 3,649 and 3,658 times that of the electron and average lifetimes of 4.2 X 10-13 and 1.1 X 10-12 seconds, respectively. See Table at subatomic particle.
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