Hyperkahler sigma models on cotangent bundles of Hermitian symmetric   spaces using projective superspace
  Kahler manifolds have a natural hyperkahler structure associated with (part of) their cotangent bundles. Using projective superspace, we construct four-dimensional N = 2 models on the tangent bundles of some classical Hermitian symmetric spaces (specifically, the four regular series of irreducible compact symmetric Kahler manifolds, and their non-compact versions). A further dualization yields the Kahler potential for the hyperkahler metric on the cotangent bundle. 
Masato Arai, Sergei M. Kuzenko, Ulf Lindstrom