Particles: Suppose you were to try to create a proton-antiproton pair by annihilation of two very high-energy gamma rays of the same wavelength heading toward each other. The proton and the anti-proton have the same masses, but opposite charges. What would be the minimum energy needed for each photon? (e = 1.60 × 10^-19 C, m_proton = 1.67 × 10^-27 kg, c = 3.00 × 10⁸ m/s) A) 1.022 MeV B) 12.2 MeV C) 1880 MeV D) 939 MeV E) 223 MeV

Question

Quizplus · Accepted Answer

The minimum energy needed for each photon to create a proton-antiproton pair is determined by the rest mass energy of the proton (or antiproton), which is given by the equation E=mc^2. The rest mass of a proton is 1.67 × 10^-27 kg, and the speed of light (c) is 3.00 × 10^8 m/s. Plugging these values into the equation gives E = (1.67 × 10^-27 kg)(3.00 × 10^8 m/s)^2 = 1.503 × 10^-10 J. Converting this energy to MeV (1 J = 6.242 × 10^12 MeV), we get approximately 939 MeV. Therefore, each photon must have a minimum energy of 939 MeV to create a proton-antiproton pair.

Particles: Suppose You Were to Try to Create a Proton-Antiproton