electron

https://doi.org/10.1351/goldbook.E01975
Elementary particle not affected by the strong force having a spin quantum number \(\frac{1}{2}\), a negative @E02032@ and a rest mass of \(0.000\ 548\ 579\ 903(13)\ \text{u}\).
Source:
Green Book, 2nd ed., p. 93 [Terms] [Book]