Lee, T.D.; Yang, C.N.; Charge Conjugation, a New Quantum Number G, and Selection Rules Concerning a Nucleon-Antinucleon System
Nuovo Cim. 3 (1956) 749;
A new quantum number is introduced which leads to selection rules concerning transitions between state with heavy particles number = 0. They are applied to the system nucleon-antinucleon; it is also shown that they can be extended to include the conservation of strangeness.
Related references See also L. Wolfenstein and D. G. Ravenhall, Phys. Rev. 88 (1952) 279;
A. Pais and R. Jost, Phys. Rev. 87 (1952) 871;
T. Nakano and K. Nishijima, Progr. of Theor. Phys. 10 (1953) 581;
D. Amati and B. Vitale, Nuovo Cim. 2 (1955) 719;
L. Michel, Nuovo Cim. 10 (1953) 319;
Invention of G-parity for nonstrange mesons.