Non-Abelian gauge fields as Nambu-Goldstone fields

Gauge invariance is obtained as a consequence of the spontaneous breaking of a larger symmetry. The Yang-Mills gauge fields are the corresponding Nambu-Goldstone fields. This involves the study of field theories in a space with more than four dimensions. In a "cylindrical" sector these field theories reduce to new non-Abelian generalizations of Jordan-Brans-Dicke theory. The nonobservability of the excess dimensions (while a difficulty for theories in which these dimensions are bosonic) should cause no problems if the higher dimensions are fermionic. In the latter case, field theories in which all basic fields are at the same time Nambu-Goldstone and Yang-Mills fields become possible. The relation of this work to recent work on gravitation theory by Yang is explored.