4
votes
3answers
133 views

How quark electric charge directly have been measured?

How quarks electric charge directly have been measured when quarks never directly observed in isolation? (Due to a phenomenon known as color confinement.)
3
votes
1answer
145 views

Origin of electric charge

Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they ...
3
votes
1answer
234 views

What's the deepest reason why QCD bound states have integer charge?

What's the deepest reason why QCD bound states have integer electric charge, i.e. equal to an integer times the electron charge? Given that the quarks have the fractional electric charges they do, ...
10
votes
4answers
2k views

Why do electron and proton have the same but opposite electric charge?

What is the explanation between equality of proton and electron charges (up to a sign)? This is connected to the gauge invariance and renormalization of charge is connected to the renormalization of ...