Angular momentum in particle interaction

[johne1618]

Imagine that two electrons interact by exchanging a virtual photon.

Electron A gains momentum $-\vec{p}$ and electron B gains momentum $\vec{p}$.

If the two momentum vectors are not collinear then there will be extra angular momentum left over from the interaction.

In a simple Coulomb interaction the momenta of A and B are collinear but I would have thought that in a general interaction they would not be. In that case how would angular momentum be conserved?

PS As the photon is virtual there isn't anything left in the EM field.

 

[mfb]

In a simple Coulomb interaction the momenta of A and B are collinear but I would have thought that in a general interaction they would not be.

Why do you think that?

 

[johne1618]

Why do you think that?

I can only think in classical terms using the Lienard-Wiechert theory.

If electron A has an acceleration perpendicular to the line A-B then electron B will receive some momentum perpendicular to A-B opposite A's acceleration.

Therefore the total momentum, $\vec{p}$, transferred to B will not be parallel to A-B.