Classical solution in six-dimensional gauge theory with higher derivative coupling

We show that the spin connection of the standard metric on a six-dimensional sphere gives an exact solution to the generalized self-duality equations suggested by Tchrakian some years ago. We work on a SO(6) gauge theory with a higher-derivative coupling term. The model consists of vector fields only. The pseudoenergy is bounded from below by a topological charge, which is proportional to the winding number of spatial S5 around the internal space SO(6). The fifth homotopy group of SO(6) is, indeed, Z. The coupling constant of the higher derivative term is quadratic in the radius of the underlying space S6.