1. The problem statement, all variables and given/known data A high energy photon moving to the right strikes a proton that is moving to the right at a speed u/c= 0.40 in the laboratory frame, creating a proton and a neutron: γ + p → p + n For the purposes of this question, assume that protons and neutrons have an equal mass m. a) What is the minimum energy that the photon must have in order for this nuclear reaction to occur? (answer in units of mc2 ) b) For the conditions in part a), what speed will the proton and neutron have in the laboratory frame? c) Suppose the photon was moving to the right, and the proton was moving to the left at 0.40c before the collision. Will this change the answer to a)? Why or why not? 2. Relevant equations E=Gamma*m*c^2 3. The attempt at a solution I am so confused. I simply found the gamma of the proton before collision.