(a) The minimum photon energy to create a protonantiproton pair is (1) more than, (2) the same...

Question:

(a) The minimum photon energy to create a proton–antiproton pair is (1) more than, (2) the same as, or (3) less than the minimum photon energy to create a neutron–antineutron pair. Explain.
(b) Calculate minimum photon frequency to create the proton–antiproton pair and the neutron–antineutron pair (to four significant figures).