The concept of "colliding" electrons is not the same as the collision of macroscopic objects in the classical sense. When we talk about electrons colliding, we are referring to their interaction through the electromagnetic force.
Electrons are elementary particles that are considered to be point-like, which means they have no known substructure or internal size. However, they still possess properties such as mass, charge, and momentum.
In particle physics, electron-electron collisions can occur when two electrons come close enough to interact with each other through the electromagnetic force. The electromagnetic force is one of the fundamental forces of nature and governs the interaction between charged particles.
When electrons approach each other, their electric fields interact, causing a change in their trajectories. The behavior of these interactions is described by quantum mechanics and quantum field theory, which provide mathematical frameworks to understand the behavior of elementary particles.
During such interactions, various processes can occur, such as scattering or the exchange of virtual photons, which mediate the electromagnetic interaction between the electrons. These processes can result in changes to the directions or energies of the electrons involved.
While electrons themselves are considered point-like, their interactions can still be studied and understood through the principles of quantum mechanics and the mathematical framework of quantum field theory.