Ambitwistor Strings in Four Dimensions
Abstract
We develop ambitwistor string theories for four dimensions to obtain new formulas for treelevel gauge and gravity amplitudes with arbitrary amounts of supersymmetry. Ambitwistor space is the space of complex null geodesics in complexified Minkowski space, and in contrast to earlier ambitwistor strings, we use twistors rather than vectors to represent this space. Although superficially similar to the original twistor string theories of Witten, Berkovits, and Skinner, these theories differ in the assignment of world sheet spins of the fields, rely on both twistor and dual twistor representatives for the vertex operators, and use the ambitwistor procedure for calculating correlation functions. Our models are much more flexible, no longer requiring maximal supersymmetry, and the resulting formulas for amplitudes are simpler, having substantially reduced moduli. These are supported on the solutions to the scattering equations refined according to helicity and can be checked by comparison with corresponding formulas of Witten and of Cachazo and Skinner.
 Publication:

Physical Review Letters
 Pub Date:
 August 2014
 DOI:
 10.1103/PhysRevLett.113.081602
 arXiv:
 arXiv:1404.6219
 Bibcode:
 2014PhRvL.113h1602G
 Keywords:

 11.25.Db;
 11.80.Cr;
 Properties of perturbation theory;
 Kinematical properties;
 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology
 EPrint:
 4 pages, v2 a few clarifications added as in PRL version