N=1/2 gauge theory and its instanton moduli space from open strings in   R-R background
  We derive the four dimensional N=1/2 super Yang-Mills theory from tree-level computations in RNS open string theory with insertions of closed string Ramond-Ramond vertices. We also study instanton configurations in this gauge theory and their ADHM moduli space, using systems of D3 and D(-1) branes in a R-R background. 
Marco Billo, Marialuisa Frau, Igor Pesando, Alberto Lerda