Proton/Electron Charge: Questions & Answers

[Jorjy]

I have some questions about the relationship between the charge of a proton and an electron.

Is it well understood why the charges are equal?
I understand that the quarks that make up a proton each have (+/-)1/3 charge, but I am curious why the charges balance out the way they do.

Is the charge of a positron exactly the same as a proton's charge?
How is it that different particles have the size type of charge?

Thanks.

 

[Meir Achuz]

The reason for the equality is still an open question to some extent.
BUT, we could not exist if they were not equal. There would be no neutral atoms.
Coulomb repulsion would not permit objects as large as people to exist.
AND, the equality and the quark charges aid convergence of QFT (not as important).

 

[mathman]

There is a long ongoing discussion in this forum on this subject (I started it it).