# Is there strong interaction between electrons?

I am not familiar with quantum mechanics at all. But I remember when I was at high school, we learned that strong interaction keeps protons next to each other while they repel each other because of electrostatic force ($F=\large{\frac{kq_1q_2}{r^2}}$). I saw this answer by David Z. He has written "Electron-electron collisions happen at low energy all the time". I got curious to know how is it possible? Because according to the formula above, when $r\to 0$ , $F\to \infty$. Then I saw John Rennie's comment under the other answer of the same question that was saying "collision means any close interaction causing a significant exchange of momentum" and this makes sense.

But, my questions are:

1. Is there strong interaction between electrons?

2. If two electrons approach to each other so much (I don't know how!), do they join together?

• It won't appear at tree-diagram level. It could appear at higher order loop level, e.g. arxiv.org/pdf/0902.3360v1.pdf Fig 29 (Though it is not precisely e-e interaction) Jul 4, 2016 at 4:26
• @Rodriguez How could it appear at higher order levels if leptons do not undergo strong interactions at all? Jul 4, 2016 at 13:04
• electron-electron exchange virtual photons, virtual photons exchange virtual quarks, virtual quarks involves strong force? Jul 4, 2016 at 18:15
• Electrons can form a bound pair in superconducting materials. This is caused by the electromagnetic force. It can only happen in certain materials as this requires an interaction of the electrons and the crystal atoms, cooper pairs cannot form in free space. Nov 23, 2018 at 15:02

1. They are leptons (spin- $1 \over 2$ particles that do not experience the strong nuclear force), and