- #1
pivoxa15
- 2,255
- 1
Why does pair production cannot occur except in the presence of another body? The explanation is so that linear momentum is conserved but why does a photon must first collide with something? I can see how linear momentum is conserved without a collision first. i.e. the two particles move with equal magnitude of momentum in y-axis but in oppsite directions. Their horizontal momentum is in same direction and add up to the photon's original momentum and it is all conserved.