Marginal deformations of N=4 SYM from open/closed twistor strings

Abstract We investigate how the marginal deformations of N = 4 supersymmetric Yang–Mills theory (analysed in particular by Leigh and Strassler) arise within B-model topological string theory on supertwistor space C P 3 | 4 . This is achieved by turning on a certain closed string background in the fermionic directions. Through a specific open/closed correlation function, this mode induces a correction to holomorphic Chern–Simons theory, corresponding to the self-dual part of the chiral operator added on the gauge theory side. The effect of the deformation is interpreted as non-anticommutativity between some of the odd coordinates of C P 3 | 4 . Motivated by this, we extend the twistor formalism for calculating MHV amplitudes in N = 4 SYM to these N = 1 theories by introducing a suitable star product between the wavefunctions. We check that our prescription yields the expected results to linear order in the deformation parameter.