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We investigate Yangian-invariant deformations of one-loop amplitudes in N = 4 super-Yang-Mills theory employing an algebraic representation of amplitudes. In this language, we reproduce the deformed massless box integral describing the…

High Energy Physics - Theory · Physics 2015-06-22 Johannes Broedel , Marius de Leeuw , Matteo Rosso

We establish an efficient polynomial-complexity algorithm for one-loop calculations, based on generalized $D$-dimensional unitarity. It allows automated computations of both cut-constructible {\it and} rational parts of one-loop scattering…

High Energy Physics - Phenomenology · Physics 2009-09-17 Walter T. Giele , Zoltan Kunszt , Kirill Melnikov

In this thesis, we study the all same helicity loop amplitudes in self-dual Yang-Mills and self-dual gravity. These amplitudes have long been conjectured to be interpreted as an anomaly and are recently linked to the UV divergence of…

High Energy Physics - Theory · Physics 2023-10-24 Pratik Chattopadhyay

We show that one-loop amplitudes in massless gauge theories can be determined from single cuts. By cutting a single propagator and putting it on-shell, the integrand of an n-point one-loop integral is transformed into an (n+2)-particle tree…

High Energy Physics - Theory · Physics 2008-12-25 E. W. Nigel Glover , Ciaran Williams

Recently, it has been shown that the holomorphic anomaly of unitarity cuts can be used as a tool in determining the one-loop amplitudes in N=4 super Yang-Mills theory. It is interesting to examine whether this method can be applied to more…

High Energy Physics - Theory · Physics 2010-11-15 Steven J. Bidder , N. E. J. Bjerrum-Bohr , Lance J. Dixon , David C. Dunbar

We construct the six-point NMHV one-loop amplitude in ${\cal N}=4$ supergravity using unitarity and recursion. The use of recursion requires the introduction of rational descendants of the cut-constructible pieces of the amplitude and the…

High Energy Physics - Theory · Physics 2017-01-04 David C. Dunbar , Warren B. Perkins

We consider the two-loop four-point amplitude in N=2 super QED, and show that there exists an approximate recursive structure similar to that captured by the ABDK/BDS ansatz for MHV amplitudes in N=4 super Yang-Mills. Furthermore, we…

High Energy Physics - Theory · Physics 2009-08-11 Andreas Brandhuber , Gabriele Travaglini , Massimiliano Vincon

We present a method to compute the integrands of one-loop Einstein-Yang-Mills amplitudes for any number of external gauge and gravity multiplets. Our construction relies on the double-copy structure of Einstein-Yang-Mills as…

High Energy Physics - Theory · Physics 2023-03-01 Franziska Porkert , Oliver Schlotterer

In this work, we prove the new factorization pattern for tree-level Yang-Mills (YM) amplitudes proposed in a companion paper. This pattern reveals a decomposition of amplitudes into a sum of gluings of lower-point amplitudes under specific…

High Energy Physics - Theory · Physics 2025-03-11 Yong Zhang

We show how generalised unitarity cuts in D = 4 - 2 epsilon dimensions can be used to calculate efficiently complete one-loop scattering amplitudes in non-supersymmetric Yang-Mills theory. This approach naturally generates the rational…

High Energy Physics - Theory · Physics 2009-11-11 Andreas Brandhuber , Simon McNamara , Bill Spence , Gabriele Travaglini

We construct all supergravity theories that can be obtained through factorized orbifold projections of N=8 supergravity, exposing their double-copy structure, and calculate their one-loop four-point scattering amplitudes. We observe a…

High Energy Physics - Theory · Physics 2015-06-12 John Joseph M. Carrasco , Marco Chiodaroli , Murat Gunaydin , Radu Roiban

The decomposition of a one-loop scattering amplitude into elementary functions with rational coefficients introduces spurious singularities which afflict individual coefficients but cancel in the complete amplitude. These cancellations…

High Energy Physics - Theory · Physics 2013-05-29 David C. Dunbar , James H. Ettle , Warren B. Perkins

One-loop amplitudes of gluons in supersymmetric Yang-Mills are four-dimensional cut-constructible. This means that they can be determined from their unitarity cuts. We present a new systematic procedure to explicitly carry out any finite…

High Energy Physics - Phenomenology · Physics 2009-07-09 Ruth Britto , Evgeny Buchbinder , Freddy Cachazo , Bo Feng

We present an ansatz for the planar five-loop four-point amplitude in maximally supersymmetric Yang-Mills theory in terms of loop integrals. This ansatz exploits the recently observed correspondence between integrals with simple conformal…

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

We present work on two-loop amplitudes in pure Yang-Mills theory with all gluons of identical helicity. We show how to obtain their rational terms -- the hardest parts to compute -- via well-understood one-loop unitarity techniques.

High Energy Physics - Phenomenology · Physics 2022-08-15 David A. Kosower , Sebastian Pögel

We exploit a recently found connection between special triple-cut diagrams and tree-level recursive diagrams to derive a general formula capturing the multi-particle factorisation of arbitrary one-loop amplitudes in the ABJM theory. This…

High Energy Physics - Theory · Physics 2015-06-05 Andreas Brandhuber , Gabriele Travaglini , Congkao Wen

We argue that generic one-loop scattering amplitudes in supersymmetric Yang-Mills theories can be computed equivalently with MHV diagrams or with Feynman diagrams. We first present a general proof of the covariance of one-loop non-MHV…

High Energy Physics - Theory · Physics 2009-11-11 Andreas Brandhuber , Bill Spence , Gabriele Travaglini

It has been known for some time that the standard MHV diagram formulation of perturbative Yang-Mills theory is incomplete, as it misses rational terms in one-loop scattering amplitudes of pure Yang-Mills. We propose that certain Lorentz…

High Energy Physics - Theory · Physics 2008-11-26 Andreas Brandhuber , Bill Spence , Gabriele Travaglini , Konstantinos Zoubos

We identify a large class of one-loop amplitudes for massless particles that can be constructed via unitarity from tree amplitudes, without any ambiguities. One-loop amplitudes for massless supersymmetric gauge theories fall into this…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , L. Dixon , D. C. Dunbar , D. A. Kosower

We explore the relation between resummation and explicit multi-loop calculations for QCD hard-scattering amplitudes. We describe how the factorization properties of amplitudes lead to the exponentiation of double and single poles at each…

High Energy Physics - Phenomenology · Physics 2014-11-17 George Sterman , Maria E. Tejeda-Yeomans