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Related papers: N >= 4 Supergravity Amplitudes from Gauge Theory a…

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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

We study the interplay between graviton reggeization and double-logarithmic in energy contributions to four-graviton scattering in theories with and without supersymmetry. Predictions to all orders in the gravitational coupling are given…

High Energy Physics - Theory · Physics 2012-08-17 Jochen Bartels , Lev N. Lipatov , Agustin Sabio Vera

Using the duality between color and kinematics, we construct two-loop four-point scattering amplitudes in $\mathcal{N}=2$ super-Yang-Mills (SYM) theory coupled to $N_f$ fundamental hypermultiplets. Our results are valid in $D\le 6$…

High Energy Physics - Theory · Physics 2017-09-20 Henrik Johansson , Gregor Kälin , Gustav Mogull

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 study the subleading-color (nonplanar) contributions to the four-gluon scattering amplitudes in N=4 supersymmetric SU(N) Yang-Mills theory. Using the formalisms of Catani and of Sterman and Tejeda-Yeomans, we develop explicit expressions…

High Energy Physics - Theory · Physics 2008-11-26 Stephen G. Naculich , Horatiu Nastase , Howard J. Schnitzer

Whenever the integrand of a gauge-theory loop amplitude can be arranged into a form where the BCJ duality between color and kinematics is manifest, a corresponding gravity integrand can be obtained simply via the double-copy procedure.…

High Energy Physics - Theory · Physics 2017-05-10 Zvi Bern , John Joseph Carrasco , Wei-Ming Chen , Henrik Johansson , Radu Roiban

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 present new and explicit formulae for the one-loop integrands of scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for any number of particles. The results exhibit the colour-kinematics duality in gauge theory…

High Energy Physics - Theory · Physics 2018-04-04 Yvonne Geyer , Ricardo Monteiro

We present the first numerical computation of two-loop amplitudes based on the unitarity method. As a proof of principle, we compute the four-gluon process. We discuss the new method, analyze its numerical properties and apply it to…

High Energy Physics - Phenomenology · Physics 2017-10-11 S. Abreu , F. Febres Cordero , H. Ita , M. Jaquier , B. Page , M. Zeng

We give a prescription for the computation of loop-level scattering amplitudes in pure Einstein gravity, and four-dimensional pure supergravities, using the color-kinematics duality. Amplitudes are constructed using double copies of pure…

High Energy Physics - Theory · Physics 2015-11-11 Henrik Johansson , Alexander Ochirov

The 4-loop 4-point amplitude in N=8 d=4 supergravity is UV finite due to supersymmetry. Even better UV behavior of the 4-loop 4-point amplitude, analogous to that of N=4 SYM theory, has been recently established by computation in [1]. All…

High Energy Physics - Theory · Physics 2009-10-02 Renata Kallosh

In this contribution we describe computational tools that permit the evaluation of multi-loop scattering amplitudes in N=8 supergravity, in terms of amplitudes in N=4 super-Yang-Mills theory. We also discuss the remarkable ultraviolet…

High Energy Physics - Theory · Physics 2015-05-27 Zvi Bern , John Joseph Carrasco , Lance Dixon , Henrik Johansson , Radu Roiban

The structure of scattering amplitudes in supergravity theories continues to be of interest. Recently, the amplitude for $2\rightarrow 2$ scattering in ${\cal N}=8$ supergravity was presented at three-loop order for the first time. The…

High Energy Physics - Theory · Physics 2019-09-18 Paolo Di Vecchia , Andrés Luna , Stephen G. Naculich , Rodolfo Russo , Gabriele Veneziano , Chris D. White

We present the complete four-loop four-point amplitude in N=4 super-Yang-Mills theory, for a general gauge group and general D-dimensional covariant kinematics, and including all non-planar contributions. We use the method of maximal cuts…

High Energy Physics - Theory · Physics 2011-03-03 Z. Bern , J. J. M. Carrasco , L. J. Dixon , H. Johansson , R. Roiban

Generalised unitarity techniques are used to calculate the coefficients of box and triangle integral functions of one-loop gluon scattering amplitudes in gauge theories with $N < 4$ supersymmetries. We show that the box coefficients in N=1…

High Energy Physics - Theory · Physics 2008-11-26 Steven J. Bidder , N. E. J. Bjerrum-Bohr , David C. Dunbar , Warren B. Perkins

This thesis is focused on the development of new mathematical methods for computing multi-loop scattering amplitudes in gauge theories. In this work we combine, for the first time, the unitarity-based construction for integrands, and the…

High Energy Physics - Phenomenology · Physics 2014-10-21 Ulrich Schubert

We present the explicit expressions in N=8 supergravity for the bosonic 4-particle tree and 1-loop amplitudes including vectors and scalars. We also present the candidate 4-point UV divergences in a form of helicity amplitudes,…

High Energy Physics - Theory · Physics 2009-09-29 Renata Kallosh , Ching Hua Lee , Tomas Rube

In this article actions for N=4 SYM and N=8 supergravity are formulated in terms of a chiral superfield, which contains only the physical degrees of freedom of either theory. In these new actions, which originate from the lightcone…

High Energy Physics - Theory · Physics 2011-08-29 Johannes Broedel , Renata Kallosh

In these lectures I talk about simplifications and universalities found in scattering amplitudes for gauge and gravity theories. In contrast to Ward identities, which are understood to arise from familiar symmetries of the classical action,…

High Energy Physics - Theory · Physics 2015-11-10 John Joseph M. Carrasco

Concrete calculations have pointed out that amplitudes in perturbative gravity exhibit unanticipated cancellations taming their ultraviolet behaviour independently of supersymmetry. Similar ultraviolet behaviour of N=4 super-Yang-Mills and…

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