A Note on Graviton Amplitudes for New Twistor String Theories

Understand

A new class of twistor string theories were recently constructed by Abou-Zeid, Hull and Mason.

• The most interesting one of these theories has the particle content of N=8 supergravity.
• Arguments are given for the vanishing of the (+ - -)-helicity amplitude for gravitons which suggest that this theory describes a chiral N=8 supergravity rather than Einstein supergravity.