In 1956 we observed the electron antineutrino.
The electron is first of all your concept of the electron.
The electron is a theory. But the theory is so good we can almost consider them real.
It is the fact that the electrons cannot all get on top of each other that makes tables and everything else solid.
There is one simplification at least. Electrons behave ... in exactly the same way as photons; they are both screwy, but in exactly in the same way...
Nothing happens until something moves. When something vibrates, the electrons of the entire universe resonate with it. Everything is connected.
If we ask, for instance, whether the position of the electron remains the same, we must say 'no'; if we ask whether the electron's position changes with time, we must say 'no'; if we ask whether the electron is at rest, we must say 'no'; if we ask whether it is in motion, we must say 'no'.
Nobody has ever seen an electron. Nor a thought. You can't see a thought, you can't measure, weigh, nor taste it- but thoughts are the most real things in the Galaxy.