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Recent computations of scattering amplitudes show that N=8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness…

High Energy Physics - Theory · Physics 2015-03-13 Z. Bern , J. J. Carrasco , D. Forde , H. Ita , H. Johansson

We show that the four-loop four-point amplitudes of N = 5 supergravity are ultraviolet finite in four dimensions, contrary to expectations based on supersymmetry and duality-symmetry arguments. We explain why the diagrams of any covariant…

High Energy Physics - Theory · Physics 2014-11-19 Zvi Bern , Scott Davies , Tristan Dennen

We construct the three-loop four-point amplitude of N=8 supergravity using the unitarity method. The amplitude is ultraviolet finite in four dimensions. Novel cancellations, not predicted by traditional superspace power-counting arguments,…

High Energy Physics - Theory · Physics 2008-11-26 Z. Bern , J. J. Carrasco , L. J. Dixon , H. Johansson , D. A. Kosower , R. Roiban

We analyse one-loop graviton amplitudes in the field theory limit of a genus-one string theory computation. The considered amplitudes can be dimensionally reduced to lower dimensions preserving maximal supersymmetry. The particular case of…

High Energy Physics - Theory · Physics 2008-11-26 N. E. J. Bjerrum-Bohr , Pierre Vanhove

We show that the double-copy structure of gravity forbids divergences in pure half-maximal (16 supercharge) supergravity at four and five points at one loop in D<8 and at two loops in D<6. We link the cancellations that render these…

High Energy Physics - Theory · Physics 2013-05-30 Zvi Bern , Scott Davies , Tristan Dennen , Yu-tin Huang

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…

High Energy Physics - Theory · Physics 2015-03-13 Z. Bern , J. J. Carrasco , L. J. Dixon , H. Johansson , R. Roiban

Using the method of maximal cuts, we obtain a form of the three-loop four-point scattering amplitude of N=8 supergravity in which all ultraviolet cancellations are made manifest. The Feynman loop integrals that appear have a graphical…

High Energy Physics - Theory · Physics 2009-11-13 Z. Bern , J. J. M. Carrasco , L. J. Dixon , H. Johansson , R. Roiban

The ultraviolet divergences of amplitude diagrams in maximal supergravity are investigated using the pure spinor superfield formalism in maximal supergravity, with maximally supersymmetric Yang-Mills theory for reference. We comment on the…

High Energy Physics - Theory · Physics 2015-08-18 Anna Karlsson

We examine the ultraviolet behaviour of supergravity theories as a function of dimension and number of supercharges. We do so by the computation of one and two-loop physical on-shell four point amplitudes. For maximal supergravity, our…

High Energy Physics - Theory · Physics 2007-05-23 Z. Bern , D. Dunbar , L. Dixon , B. Julia , M. Perelstien , J. Rozowsky , D. Seminara , M. Trigante

${{\cal N}=4}$ supergravity is understood to contain a $U(1)$ anomaly which manifests itself via the nonvanishing of loop-level scattering amplitudes that violate a tree-level charge conservation rule. In this letter we provide detailed…

High Energy Physics - Theory · Physics 2018-11-13 Zvi Bern , Julio Parra-Martinez , Radu Roiban

In this work we explore the properties of four-dimensional gravity integrands at large loop momenta. This analysis can not be done directly for the full off-shell integrand but only becomes well-defined on cuts that allow us to…

High Energy Physics - Theory · Physics 2019-03-27 Enrico Herrmann , Jaroslav Trnka

We use the duality between color and kinematics to simplify the construction of the complete four-loop four-point amplitude of N=4 super-Yang-Mills theory, including the nonplanar contributions. The duality completely determines the…

High Energy Physics - Theory · Physics 2012-10-17 Z. Bern , J. J. M. Carrasco , L. J. Dixon , H. Johansson , R. Roiban

In four dimensions, it has long been established that gravity coupled to matter exhibits ultraviolet divergences at one loop, irrespective of supersymmetry. Notably, the four-matter one-loop amplitudes of half-maximal supergravity coupled…

High Energy Physics - Theory · Physics 2026-04-02 Yu-tin Huang , Henrik Johansson , Michele Santagata , Congkao Wen

From general arguments, we show that one-loop n-point amplitudes in colourless theories satisfy a new type of reduction formula. These lead to the existence of cancellations beyond supersymmetry. Using such reduction relations we prove the…

High Energy Physics - Theory · Physics 2010-02-03 N. E. J. Bjerrum-Bohr , Pierre Vanhove

In these lectures I describe the remarkable ultraviolet behavior of N=8 supergravity, which through four loops is no worse than that of N=4 super-Yang-Mills theory (a finite theory). I also explain the computational tools that allow…

High Energy Physics - Theory · Physics 2015-03-17 Lance J. Dixon

In this chapter, we present a scattering-amplitudes perspective on supergravity, and describe its application to the study of ultraviolet properties of supergravity theories at high loop orders. The basic on-shell tools that make such…

High Energy Physics - Theory · Physics 2023-04-18 Zvi Bern , John Joseph M. Carrasco , Marco Chiodaroli , Henrik Johansson , Radu Roiban

String theory implies that field theories containing gravity are in a certain sense `products' of gauge theories. We make this product structure explicit up to two loops for the relatively simple case of N=8 supergravity four-point…

High Energy Physics - Theory · Physics 2010-11-15 Z. Bern , L. Dixon , D. C. Dunbar , M. Perelstein , J. S. Rozowsky

We demonstrate that pure N=4 supergravity is ultraviolet divergent at four loops. The form of the divergence suggests that it is due to the rigid U(1) duality-symmetry anomaly of the theory. This is the first known example of an ultraviolet…

High Energy Physics - Theory · Physics 2013-12-16 Zvi Bern , Scott Davies , Tristan Dennen , Alexander V. Smirnov , Vladimir A. Smirnov

We argue that recent results in string perturbation theory indicate that the four-graviton amplitude of four-dimensional N=8 supergravity might be ultraviolet finite up to eight loops. We similarly argue that the h-loop M-graviton amplitude…

High Energy Physics - Theory · Physics 2008-11-26 Michael B. Green , Jorge G. Russo , Pierre Vanhove

Conventional wisdom holds that no four-dimensional gravity field theory can be ultraviolet finite. This understanding is based mainly on power counting. Recent studies confirm that one-loop N = 8 supergravity amplitudes satisfy the…

High Energy Physics - Theory · Physics 2008-11-26 Zvi Bern , Lance J. Dixon , Radu Roiban
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