  We present a Lagrangian formulation for N=4 supersymmetric quantum-mechanical
systems describing the motion in external non-Abelian self-dual gauge fields.
For any such system, one can write a component supersymmetric Lagrangian by
introducing extra bosonic variables with topological Chern-Simons type
interaction. For a special class of such system when the fields are expressed
in the `t Hooft ansatz form, it is possible to give a superfield description
using harmonic superspace formalism. As a new explicit example, the N=4
mechanics with Yang monopole is constructed.

High Energy Physics - Theory