Composite Operators in the Twistor Formulation of $\mathcal{N}=4$ SYM   Theory
  We incorporate gauge-invariant local composite operators into the twistor-space formulation of $\mathcal{N}=4$ Super Yang-Mills theory. In this formulation, the interactions of the elementary fields are reorganized into infinitely many interaction vertices and we argue that the same applies to composite operators. To test our definition of the local composite operators in twistor space, we compute several corresponding form factors, thereby also initiating the study of form factors using the position twistor-space framework. Throughout this letter, we use the composite operator built from two identical complex scalars as a pedagogical example; we treat the general case in a follow-up paper. 
Laura Koster, Vladimir Mitev, Matthias Staudacher, Matthias Wilhelm
hep-th math-ph math.MP