Perturbative expansion of N<8 Supergravity
Abstract
We characterise the one-loop amplitudes for N=6 and N=4 supergravity in four dimensions. For N=6 we find that the one-loop n-point amplitudes can be expanded in terms of scalar box and triangle functions only. This simplification is consistent with a loop momentum power count of n-3, which we would interpret as being n+4 for gravity with a further -7 from the N=6 superalgebra. For N=4 we find that the amplitude is consistent with a loop momentum power count of n, which we would interpret as being n+4 for gravity with a further -4 from the N=4 superalgebra. Specifically the N=4 amplitudes contain non-cut-constructible rational terms.
Cite
@article{arxiv.1011.5378,
title = {Perturbative expansion of N<8 Supergravity},
author = {David C. Dunbar and James H. Ettle and Warren B. Perkins},
journal= {arXiv preprint arXiv:1011.5378},
year = {2011}
}
Comments
13 pages. v2 adds analytic expression for rational parts of 5-pt 1-loop N=4 SUGRA amplitude; v3 normalisations clarified