Experiments to measure it:
The 2019 redefinition of the SI base units defines it precisely and uses it as a measure of charge: https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units#Ampere
- Electron | 11, 137, 3
- Elementary particle | 0, 2k, 43
- Subatomic particle | 0, 2k, 45
- Standard Model | 92, 3k, 51
- Particle physics | 140, 19k, 291
- Physics | 276, 25k, 429
- Natural science | 0, 30k, 686
- Science | 0, 36k, 821
- Ciro Santilli's Homepage | 238, 147k, 2k
- Spin | 227, 519, 11