Thursday, December 6, 2012

1212.1146 (John Joseph M. Carrasco et al.)

One-loop four-point amplitudes in pure and matter-coupled N <= 4
supergravity
   [PDF]

John Joseph M. Carrasco, Marco Chiodaroli, Murat Gunaydin, Radu Roiban
We construct all supergravity theories that can be obtained through factorized orbifold projections of N=8 supergravity, exposing their double-copy structure, and calculate their one-loop four-point scattering amplitudes. We show that these amplitudes are identical for the two different realizations of N=4 supergravity with two vector multiplets, and argue that this feature extends to all multiplicities and loop orders as well as to higher dimensions. We also construct a selected set of supergravities obtained through a non-factorized orbifold action. Furthermore we calculate one-loop four-point amplitudes for all pure super-Yang-Mills theories with less-than-maximal supersymmetry using the duality between color and kinematics. We recover the related factorized supergravity amplitudes of N<=4 supergravity employing the double-copy construction. We observe a requirement that the four-point loop-level amplitudes have non-local integrand representations, exhibiting a mild non-locality in the form of inverse powers of the three external Mandelstam invariants. These are the first loop-level color-kinematic-satisfying representations in reduced supersymmetry theories.
View original: http://arxiv.org/abs/1212.1146

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