Gauge fields on Riemann-Cartan space-times
Gauge fields are described on an Riemann-Cartan space-time by means of tensor-valued differential forms and exterior calculus. It is shown that minimal coupling procedure leads to a gauge invariant theory where gauge fields interact with torsion, and that consistency conditions for the gauge fields impose restrictions in the non-Riemannian structure of space-time. The new results differ from the well established ones obtained by using minimal coupling procedure at the action formulation. The sources of these differences are pointed out and discussed.