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Related papers: Global Bases for Nonplanar Loop Integrands, Genera…

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Multi-loop scattering amplitudes constitute a serious bottleneck in current high-energy physics computations. Obtaining new integrand level representations with smooth behaviour is crucial for solving this issue, and surpassing the…

High Energy Physics - Phenomenology · Physics 2021-09-17 German F. R. Sborlini

In this presentation, we review the general features of integrand-reduction techniques, with a particular focus on their generalization beyond one loop. We start with a brief discussion of the one-loop scenario, a case in which…

High Energy Physics - Phenomenology · Physics 2016-08-01 Giovanni Ossola

We propose a first implementation of the integrand-reduction method for two-loop scattering amplitudes. We show that the residues of the amplitudes on multi-particle cuts are polynomials in the irreducible scalar products involving the loop…

High Energy Physics - Phenomenology · Physics 2015-05-30 Pierpaolo Mastrolia , Giovanni Ossola

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 present recent developments on the topic of the integrand reduction of scattering amplitudes. Integrand-level methods allow to express an amplitude as a linear combination of Master Integrals, by performing operations on the…

High Energy Physics - Phenomenology · Physics 2013-12-06 Hans van Deurzen , Gionata Luisoni , Pierpaolo Mastrolia , Edoardo Mirabella , Giovanni Ossola , Tiziano Peraro , Ulrich Schubert

The integrand-level methods for the reduction of scattering amplitudes are well-established techniques, which have already proven their effectiveness in several applications at one-loop. In addition to the automation and refinement of tools…

High Energy Physics - Phenomenology · Physics 2012-10-05 P. Mastrolia , E. Mirabella , G. Ossola , T. Peraro , H. van Deurzen

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 study a novel geometric expansion for scattering amplitudes in the planar sector of N=4 super Yang-Mills theory, in the context of the Amplituhedron which reproduces the all-loop integrand as a canonical differential form on the positive…

High Energy Physics - Theory · Physics 2024-01-01 Taro V. Brown , Umut Oktem , Shruti Paranjape , Jaroslav Trnka

In this paper, we have made the attempt to classify the integrand basis of all two-loop diagrams in pure four-dimension space-time. Our classification includes the topology of two-loop diagrams which determines the structure of…

High Energy Physics - Phenomenology · Physics 2015-06-11 Bo Feng , Rijun Huang

We develop an iterative method for constructing four-dimensional generalized unitarity cuts in $\mathcal{N} = 2$ supersymmetric Yang-Mills (SYM) theory coupled to fundamental matter hypermultiplets ($\mathcal{N} = 2$ SQCD). For iterated…

High Energy Physics - Theory · Physics 2019-10-08 Gregor Kälin , Gustav Mogull , Alexander Ochirov

We discuss recent progress in multi-loop integrand reduction methods. Motivated by the possibility of an automated construction of multi-loop amplitudes via generalized unitarity cuts we describe a procedure to obtain a general…

High Energy Physics - Phenomenology · Physics 2015-06-17 Simon Badger , Hjalte Frellesvig , Yang Zhang

We review generalized unitarity as a means for obtaining loop amplitudes from on-shell tree amplitudes. The method is generally applicable to both supersymmetric and non-supersymmetric amplitudes, including non-planar contributions. Here we…

High Energy Physics - Theory · Physics 2015-05-27 Zvi Bern , Yu-tin Huang

Recent progress in unitarity techniques for one-loop scattering amplitudes makes a numerical implementation of this method possible. We present a 4-dimensional unitarity method for calculating the cut-constructible part of amplitudes and…

High Energy Physics - Phenomenology · Physics 2009-09-17 R. K. Ellis , W. T. Giele , Z. Kunszt

We describe the unitarity approach for the numerical computation of two-loop integral coefficients of scattering amplitudes. It is well known that the leading propagator singularities of an amplitude's integrand are related to products of…

High Energy Physics - Phenomenology · Physics 2017-06-07 S. Abreu , F. Febres Cordero , H. Ita , M. Jaquier , B. Page

The duality between color and kinematics enables the construction of multiloop gravity integrands directly from corresponding gauge-theory integrands. This has led to new nontrivial insights into the structure of gravity theories, including…

High Energy Physics - Theory · Physics 2016-05-18 Zvi Bern , Scott Davies , Josh Nohle

The numerical unitarity approach has been important for obtaining reliable QCD predictions for the LHC. Here I discuss the extension of the approach beyond the leading quantum corrections for computing multi-loop amplitudes. The numerical…

High Energy Physics - Phenomenology · Physics 2017-03-27 Harald Ita

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

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

Using unitarity methods, we compute, for several massive two-dimensional models, the cut-constructible part of the one-loop 2->2 scattering S-matrices from the tree-level amplitudes. We apply our method to various integrable theories,…

High Energy Physics - Theory · Physics 2015-06-15 Lorenzo Bianchi , Valentina Forini , Ben Hoare

Recent studies of scattering amplitudes in planar N=4 SYM theory revealed the existence of a hidden dual superconformal symmetry. Together with the conventional superconformal symmetry it gives rise to powerful restrictions on the planar…

High Energy Physics - Theory · Physics 2014-11-20 G. P. Korchemsky , E. Sokatchev