  Mason and Skinner recently constructed a chiral infinite tension limit of the
Ramond-Neveu-Schwarz superstring which was shown to compute the Cachazo-He-Yuan
formulae for tree-level d=10 Yang-Mills amplitudes and the NS-NS sector of
tree-level d=10 supergravity amplitudes. In this letter, their chiral infinite
tension limit is generalized to the pure spinor superstring which computes a
d=10 superspace version of the Cachazo-He-Yuan formulae for tree-level d=10
super-Yang-Mills and supergravity amplitudes.
