# interaction of particles

by Hluf
Tags: interaction, particles
 P: 20 Hi people, I have one question, leptons and quarks are electromagnetically charged particles. Is there an electromagnetic interaction between them? Thank you for the help!
 PF Gold P: 11,045 Of course. That's how electrons and protons stay bound to each other in atoms.
 P: 20 Thank you, electrons and protons stay bound to each other in atoms because they have an integer charge but quarks have a fractional charge how they interact with leptons?
Thanks
P: 3,853

## interaction of particles

Charges with opposite sign attract, and charges with the same sign repel. It has nothing to do with whether they are integer charges or not.
 P: 20 According to the strong interaction, we can never see free quark, so how can the electron interact with up-quark or down quark? thank you for the response!
PF Gold
P: 11,045
 Quote by Hluf According to the strong interaction, we can never see free quark, so how can the electron interact with up-quark or down quark? thank you for the response!
Why wouldn't it be able to? A free quark just means a quark that isn't bound together with another quark. There's still three quarks making up each proton.
Mentor
P: 28,804
 Quote by Hluf Hi people, I have one question, leptons and quarks are electromagnetically charged particles. Is there an electromagnetic interaction between them? Thank you for the help!
 Quote by Hluf According to the strong interaction, we can never see free quark, so how can the electron interact with up-quark or down quark? thank you for the response!

First, you asked if there's any electromagnetic interaction between quarks and leptons. Presumably, you have no problem with knowing that there is an electromagnetic interaction between protons and electrons, ya?

So, naturally, I puzzle over why there is a problem with accepting that there is an electromagnetic interaction between quarks and leptons. After all, a proton is made up of 3 quarks. So if proton-electron has EM interaction, why do you have a problem with quark-lepton? having EM interaction?

Secondly, why would "strong interaction" matter on whether there is EM interaction between quark-lepton, which was your original question? It is not an either-or situation. The strong interaction only matters between quark-quark (or any hadrons). It doesn't significantly affect the EM interaction between quark-lepton. So I am puzzled why this matters. Does the fact that my charged Van de Graaf generator is on the earth, in the gravitational field, significantly affects its EM field when compared to having it float in space when there's less gravitational field?

Zz.