Assignment:
An electron moving in the positive x-direction is characterized by GAMMA = 1000 and BETA = 1 - 5 x 10^-7 which for this problem you can take as 1. A photon of energy hν, traveling at 45 degrees with respect to the x axis collides with the electron. The collision results in the creation of an electron-positron pair plus an electron.
A. Find the threshold energy of the photon, that is, the minimum energy the photon must have for this reaction to occur. Express your answer in terms of mc^2 where m = the mass of the electron.
B. Find the direction of the Center of Momentum Frame at threshold.