3. The first anti-particle to be deliberately created in the laboratory was the antiproton, in 1955. Colliders had not yet been invented, so this was done in fixed-target mode, via the reactionp +p p + p + (pp). (Every created antiproton must be accompanied by a proton, since baryon number is conserved in the strong interactions). Find the minimum beam energy in GeV required to produce antiprotons via this reaction. You may take mpc2 = 1 GeV. Hint: at the minimum (aka threshold) energy, the proton-antiproton pair is produced at rest in the center-of-mass frame. You may (should) take the mass of the antiproton to be identical to the mass of the proton