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Related papers: IR finite one-loop box scalar integral with massle…

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We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an…

High Energy Physics - Phenomenology · Physics 2008-12-18 F. Yuasa , E. de Doncker , J. Fujimoto , N. Hamaguchi , T. Ishikawa , Y. Shimizu

This article is the second of a series of three presenting an alternative method to compute the one-loop scalar integrals. It extends the results of the first article to general complex masses. Let us remind the main features enjoyed by…

High Energy Physics - Theory · Physics 2020-02-26 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

In this paper, we study systematically scalar one-loop two-, three-, and four-point Feynman integrals with complex internal masses. Our analytic results presented in this report are valid for both real and complex internal masses. The…

High Energy Physics - Phenomenology · Physics 2018-09-19 K. H. Phan , T. N. H. Pham

We provide a complete set of results for the scalar 4-point function appearing in one-loop calculations in QCD, QED, the electroweak Standard Model and popular extensions thereof. Complex internal masses, which are needed for calculations…

High Energy Physics - Phenomenology · Physics 2010-12-14 A. Denner , S. Dittmaier

We evaluate the massless one-loop hexagon integral in six dimensions. The result is given in terms of standard polylogarithms of uniform transcendental weight three, its functional form resembling the one of the remainder function of the…

High Energy Physics - Theory · Physics 2015-05-27 Vittorio Del Duca , Claude Duhr , Vladimir A. Smirnov

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

The class of the two-loop massless crossed boxes, with light-like external legs, is the final unresolved issue in the program of computing the scattering amplitudes of 2 --> 2 massless particles at next-to-next-to-leading order. In this…

High Energy Physics - Phenomenology · Physics 2009-10-31 C. Anastasiou , T. Gehrmann , C. Oleari , E. Remiddi , J. B. Tausk

Higher order coefficients of the inverse mass expansion of one-loop effective actions are obtained from a one-dimensional path integral representation. For the case of a massive scalar loop in the background of both a scalar potential and a…

High Energy Physics - Theory · Physics 2009-10-30 D. Fliegner , P. Haberl , M. G. Schmidt , C. Schubert

We apply differential equations technique to the calculation of the one-loop massless diagram with one offshell legs. Using reduction to $\epsilon$-form, we managed to obtain a simple one-fold integral representation exact in space-time…

High Energy Physics - Phenomenology · Physics 2017-02-15 Mikhail G. Kozlov

We derive an analytic representation of the ten-particle, two-loop double-box integral as an elliptic integral over weight-three polylogarithms. To obtain this form, we first derive a four-fold, rational (Feynman-)parametric representation…

High Energy Physics - Theory · Physics 2018-03-28 Jacob L. Bourjaily , Andrew J. McLeod , Marcus Spradlin , Matt von Hippel , Matthias Wilhelm

We consider the scalar integral associated to the 3-loop sunrise graph with a massless line, two massive lines of equal mass $M$, a fourth line of mass equal to $Mx$, and the external invariant timelike and equal to the square of the fourth…

High Energy Physics - Phenomenology · Physics 2009-11-07 P. Mastrolia , E. Remiddi

Based on the method developed in [K.~H.~Phan and T.~Riemann, Phys.\ Lett.\ B {\bf 791} (2019) 257], detailed analytic results for scalar one-loop two-, three-, four-point integrals in general $d$-dimension are presented in this paper. The…

High Energy Physics - Phenomenology · Physics 2020-06-24 Khiem Hong Phan

The calculation of exclusive observables beyond the one-loop level requires elaborate techniques for the computation of multi-leg two-loop integrals. We discuss how the large number of different integrals appearing in actual two-loop…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. Gehrmann , E. Remiddi

We consider, in more details than it was done previously, the effective low-energy behavior in the quantum theory of a light scalar field coupled to another scalar with much larger mass. The main target of our work is an IR decoupling of…

High Energy Physics - Theory · Physics 2019-10-29 Tiago G. Ribeiro , Ilya L. Shapiro

This article is the first of a series of three presenting an alternative method to compute the one-loop scalar integrals. This novel method enjoys a couple of interesting features as compared with the method closely following 't Hooft and…

High Energy Physics - Phenomenology · Physics 2020-02-13 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass…

High Energy Physics - Phenomenology · Physics 2015-06-03 F. Yuasa , E. de Doncker , N. Hamaguchi , T. Ishikawa , K. Kato , Y. Kurihara , J. Fujimoto , Y. Shimizu

Evaluation of three- and four-point diagrams with massless internal particles and arbitrary external momenta is considered. Exact results for some two-loop diagrams (planar and non-planar three-point contributions and the "double box"…

High Energy Physics - Phenomenology · Physics 2007-05-23 N. I. Ussyukina , A. I. Davydychev

This paper provides details of the massless three-loop three-point integrals calculation at the symmetric point. Our work aimed to extend known two-loop results for such integrals to the three-loop level. Obtained results can find their…

High Energy Physics - Phenomenology · Physics 2021-06-17 Andrey Pikelner

In this paper, we propose a new method for evaluating scalar one-loop Feynman integrals in generalized D-dimension. The calculations play an important building block for two-loop and higher-loop corrections to the processes at future…

High Energy Physics - Phenomenology · Physics 2017-07-10 Khiem Hong Phan

We present compact formulas for the box coefficients of the six-point NMHV one-loop amplitudes in N=8 supergravity. We explicitly demonstrate that the corresponding box integral functions, with these coefficients, have the complete IR…

High Energy Physics - Theory · Physics 2011-09-29 N. E. J. Bjerrum-Bohr , David C. Dunbar , Harald Ita