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Loop Tree Duality (LTD) offers a promising avenue to numerically integrate multi-loop integrals directly in momentum space. It is well-established at one loop, but there have been only sparse numerical results at two loops. We provide a…

High Energy Physics - Phenomenology · Physics 2019-10-16 Zeno Capatti , Valentin Hirschi , Dario Kermanschah , Ben Ruijl

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

In this paper we discuss techniques, which lead to a significant improvement of the efficiency of the Monte Carlo integration, when one-loop QCD amplitudes are calculated numerically with the help of the subtraction method and contour…

High Energy Physics - Phenomenology · Physics 2015-06-05 Sebastian Becker , Christian Reuschle , Stefan Weinzierl

The Local Unitarity (LU) formalism provides a constructive, integrand-level realisation of the Kinoshita-Lee-Nauenberg (KLN) theorem, by combining loop and phase-space integrals appearing in scattering cross-sections in such a way that…

High Energy Physics - Phenomenology · Physics 2026-03-26 Zeno Capatti , Mathijs Fraaije , Valentin Hirschi , Lucien Huber , Ben Ruijl , Hua-Sheng Shao

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

The abundance of infrared singularities in gauge theories due to unresolved emission of massless particles (soft and collinear) represents the main difficulty in perturbative calculations. They are typically regularized in dimensional…

High Energy Physics - Phenomenology · Physics 2016-03-23 Roger J. Hernandez-Pinto , German F. R. Sborlini , German Rodrigo

A method for calculating phase-space master integrals for the decay process $1 \to n$ massless partons in QCD using integration-by-parts and differential equations techniques is discussed. The method is based on the appropriate choice of…

High Energy Physics - Phenomenology · Physics 2016-03-23 O. Gituliar

We present an algorithm for the numerical calculation of one-loop QCD amplitudes. The algorithm consists of subtraction terms, approximating the soft, collinear and ultraviolet divergences of one-loop amplitudes and a method to deform the…

High Energy Physics - Phenomenology · Physics 2010-12-09 Sebastian Becker , Christian Reuschle , Stefan Weinzierl

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

Construction of a QCD cascade at the NLO level requires recalculation of the splitting functions in a different manner [1]. We describe the calculation of some of the virtual contributions to the non-singlet splitting function. In order to…

High Energy Physics - Phenomenology · Physics 2015-06-17 O. Gituliar , S. Jadach , A. Kusina , M. Skrzypek

We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector…

High Energy Physics - Phenomenology · Physics 2017-05-24 Fabrizio Caola , Kirill Melnikov , Raoul Röntsch

We present a new general algorithm for calculating arbitrary jet cross sections in arbitrary scattering processes to next-to-leading accuracy in perturbative QCD. The algorithm is based on the subtraction method. The key ingredients are new…

High Energy Physics - Phenomenology · Physics 2009-10-28 Stefano Catani , Michael H. Seymour

We compute the next-to-leading order (NLO) QCD corrections to the $1 \to 2$ splitting amplitudes in different dimensional regularization (DREG) schemes. Besides recovering previously known results, we explore new DREG schemes and analyze…

High Energy Physics - Phenomenology · Physics 2014-01-15 German F. R. Sborlini , Daniel de Florian , German Rodrigo

We briefly describe a new general algorithm for carrying out QCD calculations to next-to-leading order in perturbation theory. The algorithm can be used for computing arbitrary jet cross sections in arbitrary processes and can be…

High Energy Physics - Phenomenology · Physics 2015-06-25 Stefano Catani , Michael H. Seymour

The Loop-Tree Duality (LTD) is a novel perturbative method in QFT that establishes a relation between loop-level and tree-level amplitudes, which gives rise to the idea of treating them simultaneously in a common Monte Carlo. Initially…

High Energy Physics - Phenomenology · Physics 2015-10-15 Sebastian Buchta

We use dimensional regularization to evaluate quantum mechanical path integrals in arbitrary curved spaces on an infinite time interval. We perform 3-loop calculations in Riemann normal coordinates, and 2-loop calculations in general…

High Energy Physics - Theory · Physics 2009-10-31 F. Bastianelli , O. Corradini , P. van Nieuwenhuizen

We propose a new method of computing real emission contributions to hard QCD processes. Our approach uses sector decomposition of the exclusive final-state phase space to enable extraction of all singularities of the real emission matrix…

High Energy Physics - Phenomenology · Physics 2008-11-26 C. Anastasiou , Kirill Melnikov , Frank Petriello

The calculation of exclusive cross sections at next-to-next-to-leading order (NNLO) in QCD requires an analytic understanding of the infrared singular structure with up to two unresolved partons. This has so far only been achieved for…

High Energy Physics - Phenomenology · Physics 2024-08-22 Thomas Gehrmann , Markus Löchner

Within the framework of local analytic sector subtraction, we present the full analytic integration of double-real and real-virtual local infrared counterterms that enter NNLO QCD computations with any number of massless final-state…

High Energy Physics - Phenomenology · Physics 2022-01-17 Lorenzo Magnea , Giovanni Pelliccioli , Chiara Signorile-Signorile , Paolo Torrielli , Sandro Uccirati

I apply FDR -- a recently introduced Four Dimensional Regularization approach to quantum field theories -- to compute the NLO QCD corrections to H -> gg in the large top mass limit. The calculation involves all key ingredients of massless…

High Energy Physics - Phenomenology · Physics 2014-01-24 Roberto Pittau