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In the past years, we have been developing a novel technique, called Four-Dimensional Unsubtraction (FDU) which aims to obtain purely four-dimensional representations of the matrix elements contributing to physical observables. In this…

High Energy Physics - Phenomenology · Physics 2019-11-05 German F. R. Sborlini

In the context of high-energy particle physics, a reliable theory-experiment confrontation requires precise theoretical predictions. This translates into accessing higher-perturbative orders, and when we pursue this objective, we inevitably…

High Energy Physics - Phenomenology · Physics 2024-09-12 German Sborlini

We describe the calculation of the one-loop corrections to $H \to \gamma \gamma$ and $g g \to H$ within the four-dimensional unsubtraction/loop-tree duality (FDU/LTD) approach. The fact that these corrections are both IR and UV finite is…

High Energy Physics - Phenomenology · Physics 2017-09-29 German F. R. Sborlini , Felix Driencourt-Mangin , German Rodrigo

Loop-tree duality allows to express virtual contributions in terms of phase-space integrals, thus leading to a direct comparison with real radiation terms. In this talk, we review the basis of the method and describe its application to…

High Energy Physics - Phenomenology · Physics 2016-01-21 German F. R. Sborlini

We present a first numerical implementation of the Loop-Tree Duality (LTD) method for the direct numerical computation of multi-leg one-loop Feynman integrals. We discuss in detail the singular structure of the dual integrands and define a…

High Energy Physics - Phenomenology · Physics 2015-10-06 Sebastian Buchta , Grigorios Chachamis , Petros Draggiotis , German Rodrigo

In this review, we discuss recent developments concerning efficient calculations of multi-loop multi-leg scattering amplitudes. Inspired by the remarkable properties of the Loop-Tree Duality (LTD), we explain how to reconstruct an integrand…

High Energy Physics - Phenomenology · Physics 2021-09-30 German F. R. Sborlini

We present the analytic and compact two-loop helicity amplitudes for QCD and QED corrections to the light-by-light scattering process with massive internal fermions. We express the master integrals either in terms of multiple polylogarithms…

High Energy Physics - Phenomenology · Physics 2024-03-22 Ajjath A H , Ekta Chaubey , Hua-Sheng Shao

An explicit Loop Tree Duality (LTD) formula for two-loop Feynman integrals with integer power of propagators is presented and used for a numerical UV divergence subtraction algorithm. This algorithm proceeds recursively and it is based on…

High Energy Physics - Phenomenology · Physics 2024-09-04 Daniele Artico

Though the one-loop amplitudes of the Higgs boson to massless gauge bosons are finite because there is no direct interaction at tree-level in the Standard Model, a well-defined regularization scheme is still required for their correct…

High Energy Physics - Phenomenology · Physics 2018-03-22 Felix Driencourt-Mangin , German Rodrigo , German F. R. Sborlini

The loop-tree duality (LTD) has become a novelty alternative to bootstrap the numerical evaluation of multi-loop scattering amplitudes. It has indeed been found that Feynman integrands, after the application of LTD, display a representation…

High Energy Physics - Phenomenology · Physics 2021-10-29 William J. Torres Bobadilla

The success of the spinor helicity technique for tree processes is reviewed. To apply it to multiloop diagrams one is naturally led to the Schwinger proper-time representation, whose properties are discussed. This representation also serves…

High Energy Physics - Phenomenology · Physics 2009-09-25 C. S. Lam

We present a new method for computing multi-loop scattering amplitudes in Quantum Field Theory. It extends the Generalized Unitarity method by constraining not only the integrand of the amplitude but also its full integrated form. Our…

High Energy Physics - Theory · Physics 2025-12-18 Piotr Bargiela

The numerical evaluation of multi-loop scattering amplitudes in the Feynman representation usually requires to deal with both physical (causal) and unphysical (non-causal) singularities. The loop-tree duality (LTD) offers a powerful…

We present advances in the development of the numerical unitarity method for the computation of multi-loop amplitudes in QCD. As an application, we show results for all the leading-color two-loop five-gluon helicity amplitudes. The…

High Energy Physics - Phenomenology · Physics 2018-07-26 Samuel Abreu , Fernando Febres Cordero , Harald Ita , Ben Page , Mao Zeng

We introduce a novel construction of a contour deformation within the framework of Loop-Tree Duality for the numerical computation of loop integrals featuring threshold singularities in momentum space. The functional form of our contour…

High Energy Physics - Phenomenology · Physics 2020-11-24 Zeno Capatti , Valentin Hirschi , Dario Kermanschah , Andrea Pelloni , Ben Ruijl

We present an overview of the analysis of the multiloop topologies that appear for the first time at four loops and the assembly of them in a general expression, the N$^4$MLT universal topology. Based on the fact that the Loop-Tree Duality…

Loop-tree duality (LTD) allows to express virtual contributions in terms of phase-space integrals, thus leading to a direct mapping with real radiation terms. We review the basis of the method and describe its application to regularize…

High Energy Physics - Phenomenology · Physics 2015-10-19 German F. R. Sborlini , Roger Hernandez-Pinto , German Rodrigo

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

We compute the two-loop helicity amplitudes for the scattering of five gluons, including all contributions beyond the leading-color approximation. The analytic expressions are represented as linear combinations of transcendental functions…

High Energy Physics - Phenomenology · Physics 2024-05-15 Giuseppe De Laurentis , Harald Ita , Maximillian Klinkert , Vasily Sotnikov

We present the two-loop helicity amplitudes for the scattering of massless quarks in QCD. We use projector techniques to compute the coefficients of the general four-quark amplitude at up to two-loops in conventional dimensional…

High Energy Physics - Phenomenology · Physics 2009-11-10 E. W. N. Glover