Off-shell D=5, N=2 Riemann Squared Supergravity
  We construct a new off-shell invariant in N=2, D=5 supergravity whose leading term is the square of the Riemann tensor. It contains a gravitational Chern-Simons term involving the vector field that belongs to the supergravity multiplet. The action is obtained by mapping the transformation rules of a spin connection with bosonic torsion and a set of curvatures to the fields of the Yang-Mills multiplet with gauge group SO(4,1). We also employ the circle reduction of an action that describes locally supersymmetric Yang-Mills theory in six dimensions. 
Eric A. Bergshoeff, Jan Rosseel, Ergin Sezgin
hep-th