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Related papers: Unitarity and On-Shell Recursion Methods for Scatt…

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In this letter, we exploit generalised unitarity in order to calculate the cut-constructible part of one-loop amplitudes in non-supersymmetric Yang-Mills theory. In particular, we rederive the n-gluon MHV amplitudes for both the adjacent…

High Energy Physics - Phenomenology · Physics 2010-02-03 Andreas Brandhuber , Massimiliano Vincon

Some effective field theories exhibit dynamical resonances that, when properly included, mitigate their bad behaviour at high energies. Unitarization of the partial wave amplitudes is the preferred method to unveil such resonances.…

High Energy Physics - Theory · Physics 2023-03-15 Rafael L. Delgado , Antonio Dobado , Domènec Espriu

We present and prove a formula for the MHV scattering amplitude of n gravitons at tree level. Some of the more interesting features of the formula, which set it apart as being significantly different from many more familiar formulas,…

High Energy Physics - Theory · Physics 2011-03-28 Dung Nguyen , Marcus Spradlin , Anastasia Volovich , Congkao Wen

We demonstrate that loop integrands of (super-)gravity scattering amplitudes possess surprising properties in the ultraviolet (UV) region. In particular, we study the scaling of multi-particle unitarity cuts for asymptotically large momenta…

High Energy Physics - Theory · Physics 2021-02-16 Alex Edison , Enrico Herrmann , Julio Parra-Martinez , Jaroslav Trnka

We prove that the MHV vertex expansion is valid for any NMHV tree amplitude of N=4 SYM. The proof uses induction to show that there always exists a complex deformation of three external momenta such that the amplitude falls off at least as…

High Energy Physics - Theory · Physics 2009-04-17 Henriette Elvang , Daniel Z. Freedman , Michael Kiermaier

By analytically continuing QCD scattering amplitudes through specific complexified momenta, one can study and learn about the nature and the consequences of factorization and unitarity. In some cases, when coupled with the largest time…

High Energy Physics - Theory · Physics 2008-11-26 Diana Vaman , York-Peng Yao

We review the recently developed bootstrap method for the computation of high-multiplicity QCD amplitudes at one loop. We illustrate the general algorithm step by step with a six-point example. The method combines (generalized) unitarity…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger

We develop a formalism, based on spinor-helicity techniques, to generalize the formulation of partial wave unitarity bounds. We discuss unitarity bounds for $N \to M$ (with $N,M \geq 2$) scattering processes -- relevant for high-energy…

High Energy Physics - Phenomenology · Physics 2026-05-26 Luigi C. Bresciani , Gabriele Levati , Paride Paradisi

In this work, the massless-massive correspondence for the on-shell scattering amplitudes is constructed so the massive amplitudes could inherit advantageous techniques developed in the massless calculation. This correspondence is…

High Energy Physics - Phenomenology · Physics 2026-01-16 Yu-Han Ni , Chao Wu , Jiang-Hao Yu

The maximally helicity violating (MHV) tree level scattering amplitudes involving three, four or five gravitons are worked out in Unimodular Gravity. They are found to coincide with the corresponding amplitudes in General Relativity. This a…

High Energy Physics - Theory · Physics 2018-02-15 Enrique Alvarez , Sergio Gonzalez-Martin , Carmelo P. Martin

We study the application of recursion relations to the calculation of finite one-loop gravity amplitudes. It is shown explicitly that the known four, five, and six graviton one-loop amplitudes for which the external legs have identical…

High Energy Physics - Theory · Physics 2010-10-27 Andreas Brandhuber , Simon McNamara , Bill Spence , Gabriele Travaglini

We present a novel framework for computing differential cross-sections in quantum field theory using the optical theorem and loop amplitudes, circumventing the traditional method of squaring scattering amplitudes. This approach addresses…

High Energy Physics - Phenomenology · Physics 2024-12-16 Vatsal Garg , Hojin Lee , Kanghoon Lee

In this review we describe a non-trivial relationship between perturbative gauge theory and gravity scattering amplitudes. At the semi-classical or tree level, the scattering amplitudes of gravity theories in flat space can be expressed as…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Zvi Bern

We show how the MHV diagram description of Yang-Mills theories can be used to study non-supersymmetric loop amplitudes. In particular, we derive a compact expression for the cut-constructible part of the general one-loop MHV multi-gluon…

High Energy Physics - Theory · Physics 2010-12-14 James Bedford , Andreas Brandhuber , Bill Spence , Gabriele Travaglini

We discuss recursion relations for scattering amplitudes with massive particles of any spin. They are derived via a two-parameter shift of momenta, combining a BCFW-type spinor shift with the soft limit of a massless particle involved in…

High Energy Physics - Theory · Physics 2023-01-11 Adam Falkowski , Camila S. Machado

Invariance of on-shell scattering amplitudes under field redefinitions is a well known property in field theory that corresponds to covariance of on-shell amputated connected functions. In recent years there have been great efforts to…

High Energy Physics - Theory · Physics 2026-03-06 Mohammad Alminawi

These lectures are centred around tree-level scattering amplitudes in pure Yang-Mills theories, the most prominent example is given by the tree-level gluon amplitudes of QCD. I will discuss several ways of computing these amplitudes,…

High Energy Physics - Theory · Physics 2017-01-23 Stefan Weinzierl

This article reviews the recent progress in twistor approaches to Wilson loops, amplitudes and their duality for N=4 super Yang-Mills. Wilson loops and amplitudes are derived from first principles using the twistor action for maximally…

High Energy Physics - Theory · Physics 2015-05-27 Tim Adamo , Mathew Bullimore , Lionel Mason , David Skinner

We present unitarity as a method for determining the infinities present in graviton scattering amplitudes. The infinities are a combination of IR and UV. By understanding the soft singularities we may extract the UV infinities and relate…

High Energy Physics - Theory · Physics 2009-10-28 D. C. Dunbar , P. S. Norridge

The scattering equations on the Riemann sphere give rise to remarkable formulae for tree-level gauge theory and gravity amplitudes. Adamo, Casali and Skinner conjectured a one-loop formula for supergravity amplitudes based on scattering…

High Energy Physics - Theory · Physics 2015-09-23 Yvonne Geyer , Lionel Mason , Ricardo Monteiro , Piotr Tourkine