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We propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes. In our formulation particles propagating inside the loop are represented by massive internal states regulating the…

High Energy Physics - Phenomenology · Physics 2014-04-21 Raffaele A. Fazio , Pierpaolo Mastrolia , Edoardo Mirabella , William J. Torres Bobadilla

Constrained Differential Renormalization (CDR) and the constrained version of Implicit Regularization (IR) are two regularization independent techniques that do not rely on dimensional continuation of the space-time. These two methods which…

High Energy Physics - Theory · Physics 2008-11-26 Carlos R. Pontes , A. P. Baêta Scarpelli , Marcos Sampaio , J. L. Acebal , M. C. Nemes

We compute the two-loop corrections to the massless quark form factor $\gamma^* \to q\bar q$ and gluon form factor $H\to gg$ to all orders in the dimensional regularisation parameter $\epsilon=(4-d)/2$. The two-loop contributions to the…

High Energy Physics - Phenomenology · Physics 2021-11-04 T. Gehrmann , T. Huber , D. Maitre

So far, the use of different variants of dimensional regularization has been investigated extensively for two-loop virtual corrections. We extend these studies to real corrections that are also required for a complete computation of…

High Energy Physics - Phenomenology · Physics 2020-04-22 Christoph Gnendiger , Adrian Signer

We derive the complete set of two-loop anomalous dimensions describing the mixing of four-fermion operators in the Low Energy Effective Field Theory (LEFT). The calculation is performed in Naive Dimensional Regularization with anticommuting…

High Energy Physics - Phenomenology · Physics 2026-05-08 Jason Aebischer , Pol Morell , Marko Pesut , Javier Virto

We show that, by viewing a 4D effective-field theory as the infrared (IR) limit of the compactified version in 5D, we can compute two-loop anomalous dimensions without gauge-breaking counter-terms, IR re-arrangement or geometric methods.…

High Energy Physics - Phenomenology · Physics 2025-12-04 Mikael Chala , Javier López Miras

We clarify a discrepancy between two previous calculations of the two-loop QED Euler-Heisenberg Lagrangian, both performed in proper-time regularization, by calculating this quantity in dimensional regularization.

High Energy Physics - Theory · Physics 2008-11-26 Denny Fliegner , Martin Reuter , Michael G. Schmidt , Christian Schubert

The calculation of hard scattering amplitudes up to NLO is automated in numerical tools, such as OpenLoops. The LHC and future experiments, however, demand high-precision predictions at NNLO and beyond for a wide range of particle…

High Energy Physics - Phenomenology · Physics 2024-12-20 Natalie Schär , Max F. Zoller

The use of the dimensional regularization in the on-mass-shell renormalization scheme sometimes fails to locally cancel the ultraviolet divergence for a class of diagrams in the two-loop order. The mechanism is discussed based on an example…

High Energy Physics - Phenomenology · Physics 2024-03-19 Kiyoshi Kato

We use the antenna subtraction method to isolate the double virtual infrared singularities present in gluonic scattering amplitudes at next-to-next-to-leading order. In previous papers, we derived the subtraction terms that rendered (a) the…

High Energy Physics - Phenomenology · Physics 2015-06-12 Aude Gehrmann-De Ridder , Thomas Gehrmann , E. W. N. Glover , Joao Pires

The consistency of loop regularization (LORE) method is explored in multiloop calculations. A key concept of the LORE method is the introduction of irreducible loop integrals (ILIs) which are evaluated from the Feynman diagrams by adopting…

High Energy Physics - Phenomenology · Physics 2015-05-30 Da Huang , Yue-Liang Wu

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

We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , A. De Freitas , L. Dixon , H. L. Wong

The $H\to gg$ amplitude relevant for Higgs production via gluon fusion is computed in the four-dimensional helicity scheme (FDH) and in dimensional reduction (DRED) at the two-loop level. The required renormalization is developed and…

High Energy Physics - Phenomenology · Physics 2015-09-30 A. Broggio , Ch. Gnendiger , A. Signer , D. Stöckinger , A. Visconti

Modeling the large-scale structure of the universe on nonlinear scales has the potential to substantially increase the science return of upcoming surveys by increasing the number of modes available for model comparisons. One way to achieve…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-30 Marcel Schmittfull , Zvonimir Vlah

We compute the two-loop $\beta$-function of scalar and spinorial quantum electrodynamics as well as pure Yang-Mills and quantum chromodynamics using the background field method in a fully quadridimensional setup using Implicit…

High Energy Physics - Phenomenology · Physics 2021-06-29 A. Cherchiglia , D. C. Arias-Perdomo , A. R. Vieira , M. Sampaio , B. Hiller

We present a novel set of Feynman rules and generalised unitarity cut-conditions for computing one-loop amplitudes via d-dimensional integrand reduction algorithm. Our algorithm is suited for analytic as well as numerical result, because…

High Energy Physics - Phenomenology · Physics 2015-05-25 W. J. Torres Bobadilla , A. R. Fazio , P. Mastrolia , E. Mirabella

We discuss the prescription for the Dirac matrix gamma_5 in dimensional regularization used in most second- and third-order QCD calculations of collider cross sections. We provide an alternative implementation of this approach that avoids…

High Energy Physics - Phenomenology · Physics 2015-06-16 S. Moch , J. A. M. Vermaseren , A. Vogt

Implicit regularization (IR) has been shown as an useful momentum space tool for perturbative calculations in dimension specific theories, such as chiral gauge, topological and supersymmetric quantum field theoretical models at one loop…

High Energy Physics - Theory · Physics 2009-11-11 C. R. Pontes , A. P. Baeta Scarpelli , Marcos Sampaio , M. C. Nemes

We study the problem how to deal with tensor-type two-loop integrals in the Loop Regularization (LORE) scheme. We use the two-loop photon vacuum polarization in the massless Quantum Electrodynamics (QED) as the example to present the…

High Energy Physics - Phenomenology · Physics 2015-06-11 Da Huang , Ling-Fong Li , Yue-Liang Wu