Ultraviolet behavior of N = 8 supergravity at four loops.
We describe the construction of the complete four-loop four-particle amplitude of N=8 supergravity. The amplitude is ultraviolet finite, not only in four dimensions, but in five dimensions as well. The observed extra cancellations provide additional nontrivial evidence that N=8 supergravity in four dimensions may be ultraviolet finite to all orders of perturbation theory.
Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547, USA.
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Z
Bern
J J M
JJ
Carrasco
L J
LJ
Dixon
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H
Johansson
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R
Roiban