Loop amplitudes in maximal supergravity with manifest supersymmetry

Artikel i vetenskaplig tidskrift, 2013

We present a description for amplitude diagrams in maximal supergravities obtained by dimensional reduction from D = 11, derived from a field the- ory point of view using the pure spinor formalism. The advantages of this approach are the manifest supersymmetry present in the formalism, and the limited number of interaction terms in the action. Furthermore, we investi- gate the conditions set by this description in order for amplitudes in maximal supergravity to be finite in the ultraviolet limit. Typically, there is an upper limit to the dimension, set by the loop order, which for an arbitrary number of loops is no larger than two. In four dimensions, the non-renormalisation power of the formalism fails for the 7-loop contribution to the 4-point am- plitude, all of which is in clear agreement with previous work.