An experimenter sets up a beam of protons which impacts a stationary liquid hydrogen target. We will call this frame of reference, in which the target is not moving, the lab frame. The protons in the beam interact with the protons in the hydrogen nuclei via the reaction : 1H + 1H rightarrow2 D + e+ + ve For the purposes of this problem, you can neglect the small momentum and energy carried by the electron neutrino ve. The rest mass energy of the proton is mpc2 = 938 MeV, the deuteron mD = 1876 MeV, and the electron mec2 = 511 keV. In the lab frame, the experimenter measures the total energy of each proton to be twice the proton's rest mass. What is its momentum, in GeV/c? The rest mass energy of the proton is mpc2 = 938 MeV.