The diagram shows the tracks of two particles, P and Q, created from an original particle at point X.
Which of the following can be concluded from this diagram?
A P and Q have equal and opposite momentum.
B The original particle had no charge.
C The original particle was stationary.
D There is a magnetic field acting into the page.
The only correct answer is B this shows pair production from a gamma photon in the
presence of a massive particle with no track until X
A is not correct because the particles do not move in opposite directions at point X
C is not correct because the particles a gamma photon cannot exist at rest
D is not correct because the charges of the particles have not been stated
