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We give numerical integration results for Feynman loop diagrams such as those covered by Laporta [1] and by Baikov and Chetyrkin [2], and which may give rise to loop integrals with UV singularities. We explore automatic adaptive integration…

High Energy Physics - Phenomenology · Physics 2018-02-05 E. de Doncker , F. Yuasa , K. Kato , T. Ishikawa , J. Kapenga , O. Olagbemi

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 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

Within the Local Unitarity formalism, any physical cross-section is re-written in such a way that cancellations of infrared singularities between real and virtual contributions are realised locally. Consequently, phase-space and loop…

High Energy Physics - Phenomenology · Physics 2021-11-01 Zeno Capatti

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

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 study two--loop renormalization in $(2+\epsilon)$--dimensional quantum gravity. As a first step towards the full calculation, we concentrate on the divergences which are proportional to the number of matter fields. We calculate the…

High Energy Physics - Theory · Physics 2016-09-06 Toshiaki Aida , Yoshihisa Kitazawa , Jun Nishimura , Asato Tsuchiya

A new symmetry-preserving loop regularization method proposed in \cite{ylw} is further investigated. It is found that its prescription can be understood by introducing a regulating distribution function to the proper-time formalism of…

High Energy Physics - Theory · Physics 2009-11-10 Yue-Liang Wu

Scattering amplitudes in $D$ dimensions involve particular terms that originate from the interplay of UV poles with the $D-4$ dimensional parts of loop numerators. Such contributions can be controlled through a finite set of…

High Energy Physics - Phenomenology · Physics 2020-10-28 Jean-Nicolas Lang , Stefano Pozzorini , Hantian Zhang , Max F. Zoller

We introduce a streamlined method for evaluating in-in loop integrals using dimensional regularization for diagrams with an arbitrary number of external legs and vertices, which complements earlier work and facilitates the extraction of the…

High Energy Physics - Theory · Physics 2026-05-15 Guillermo Ballesteros , Jesús Gambín Egea , Flavio Riccardi

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

Understanding the cancellation of ultraviolet and infrared singularities in perturbative quantum field theory is of central importance for the development and automation of various theoretical tools that make accurate predictions for…

High Energy Physics - Theory · Physics 2024-11-11 David F. Rentería-Estrada

We develop a coordinate space renormalization of massless Quantum Electrodynamics using the powerful method of differential renormalization. Bare one-loop amplitudes are finite at non-coincident external points, but do not accept a Fourier…

High Energy Physics - Phenomenology · Physics 2009-10-22 Peter E. Haagensen , Jose I. Latorre

We consider the most general loop integral that appears in non-relativistic effective field theories with no light particles. The divergences of this integral are in correspondence with simple poles in the space of complex space-time…

High Energy Physics - Theory · Physics 2008-11-26 D. R. Phillips , S. R. Beane , M. C. Birse

Loop diagram calculations typically rely on reduction to a finite set of master integrals in $4 - 2\epsilon$ dimensions. It has been shown that for any problem, the masters can be chosen so that their coefficients are finite as $\epsilon…

High Energy Physics - Phenomenology · Physics 2022-04-06 Stephen P. Martin

For supersymmetric gauge theories a consistent regularization scheme that preserves supersymmetry and gauge invariance is not known. In this article we tackle this problem for supersymmetric QED within the framework of algebraic…

High Energy Physics - Phenomenology · Physics 2011-09-13 W. Hollik , E. Kraus , D. Stöckinger

One of the most severe bottlenecks to reach high-precision predictions in QFT is the calculation of multiloop multileg Feynman integrals. Several new strategies have been proposed in the last years, allowing impressive results with deep…

High Energy Physics - Theory · Physics 2023-09-27 German F. R. Sborlini

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

Using an infinitesimal approach, this work addresses the renormalization problem to deal with the ultraviolet divergences arising in quantum field theory. Under the assumption that the action has already been renormalized to yield an…

High Energy Physics - Theory · Physics 2025-09-09 L. L. Salcedo

In the 't Hooft-Veltman dimensional regularization scheme it is necessary to introduce finite counterterms to satisfy chiral Ward identities. It is a non-trivial task to evaluate these counterterms even at two loops. We suggest the use of…

High Energy Physics - Theory · Physics 2009-10-31 M. Pernici , M. Raciti , F. Riva