Abstract
Assuming that the colored gauge group is not necessarily the SU(3) but an arbitrary simple compact Lie group, we find that cases of being one of the groups SU(2), , , Sp (), , , , and Will lead to a difficulty with the quark-line rule. Therefore, only the groups (), (), and remain to be possible candidates for . It is argued that the same restriction also applies to any unified simple group of all strong, weak, and electromagnetic interactions.
- Received 15 September 1977
DOI:https://doi.org/10.1103/PhysRevD.16.3535
©1977 American Physical Society