Bjorken, J.D.; Glashow, S.L.; Elementary Particles and SU(4)
Phys. Lett. 11 (1964) 255;

Reprinted in
J. L. Rosner, New Particles. Selected Reprints, Stony Brook, Am. Ass. of Physics Teachers (1981) 15.

Motivation
Recently, models of strong interaction symmetry have been proposed involving four fundamental Fermion fields _{i} and approximate symmetry under SU(4). Mesons are identified with bound states ,^i _{i} a nd baryons with bound states ,^i _{j}_{k}.
In this note we examine a model of this kind whose principal achievements are these: a mass formula relating the masses of the nine vector mesons and predicting a ninth pseudoscalar meson at 950 MeV, a description of weak interactions including all selection rules except the nonleptonic I = 1 / 2 rule, and a significant "baryon''-lepton symmetry. A new quantum number "charm'' is violated only by the weak interactions, and the model predicts the existence
of many "charmed'' particles whose discovery is the crucial test of the idea. (Extracted from the introductory part of the paper.).

Related references See also M. Gell-Mann, Phys. Lett. 8 (1964) 214;
M. Gell-Mann, Phys. Rev. 125 (1962) 1067;
P. Tarjanne and V. L. Teplitz, Phys. Rev. Lett. 11 (1963) 447;
Y. Hara, Phys. Rev. 134 (1964) B701;
S. Okubo, Progr. of Theor. Phys. 27 (1962) 949;
J. Schwinger, Phys. Rev. Lett. 12 (1964) 630;
M. Goldberg et al., Phys. Rev. Lett. 12 (1964) 546;
S. Coleman and S. L. Glashow, Phys. Rev. 134 (1964) B671;
N. Cabibbo, Phys. Rev. Lett. 10 (1963) 531;
A. Salam, Phys. Lett. 8 (1964) 216;
G. R. Kalbfleisch et al., Phys. Rev. Lett. 12 (1964) 527;

Particles studied

charm

ex, qn

Record comments
Proposal for the existence of a charmed fundamental fermion.