N = 1/2 quiver gauge theories from open strings with R-R fluxes

We consider a four dimensional N 1 gauge theory with bifundamental matter and a superpotential, defined on stacks of fractional branes. By turning on a flux for the R-R gravi photon field strength and computing open string amplitudes with insertions of R-R closed string vortices, we introduce a non-anticommutative deformation and obtain the N 1/2 version of the theory. We also comment on the appearance of a new structure in the effective lagrangian.