N=4 mechanics with diverse (4,4,0) multiplets: explicit examples of HKT, CKT, and OKT geometries

We present simple models of N=4 supersymmetric mechanics with ordinary and mirror linear (4,4,0) multiplets that give a transparent description of HKT, CKT, and OKT geometries. These models are treated in the N=4 and N=2 superfield approaches, as well as in the component approach. Our study makes manifest that the CKT and OKT supersymmetric sigma models are distinguished from the more simple HKT models by the presence of extra holomorphic torsions in the supercharges.