Deriving CSW rules for massive scalar legs and pure Yang-Mills loops

Understand

This article provides two complementary detailed derivations of Cachazo-Svrcek-Witten-style Feynman rules for Yang-Mills gauge theory coupled to a massive coloured scalar as presented in earlier work.

• These proceed through a direct canonical transformation method on space-time and through a gauge transformation in an action constructed on twistor space.
• It is shown explicitly that the field transformations are identical in both cases.
• Some simple tree-level examples of our rules are given and we comment on the application of them to the calculation of the rational part of one-loop pure glue amplitudes.