1203.1026 (Tim Adamo et al.)

Einstein supergravity amplitudes from twistor-string theory    [PDF]

Tim Adamo, Lionel Mason

This paper gives a twistor-string formulation for all tree amplitudes of Einstein (super-)gravities for $\cN=0$ and 4. Formulae are given with and without cosmological constant and with various possiblities for the gauging. The formulae are justified by use of Maldacena's observation that conformal gravity tree amplitudes with Einstein wave functions and non-zero cosmological constant will correctly give the Einstein tree amplitudes. This justifies the construction of Einstein gravity amplitudes at N=0 from twistor-string theory and is extended to include more supersymmetry. BCFW recursion is used to obtain twistor-string-like formulae at degree zero and one (anti-MHV and MHV) for amplitudes with N=8 supersymmetry with and without cosmological constant.

View original: http://arxiv.org/abs/1203.1026