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Decay amplitude of $H \to \gamma Z$ process via one $W$ loop in the unitary gauge is presented. The divergent integrals including those of high divergence orders typical of unitary gauge are arranged to cancel to get the electromagnetic…

High Energy Physics - Phenomenology · Physics 2023-06-21 Shi-Yuan Li

The new version 2.1 of the program SecDec is described, which can be used for the factorisation of poles and subsequent numerical evaluation of multi-loop integrals, in particular massive two-loop integrals. The program is not restricted to…

High Energy Physics - Phenomenology · Physics 2015-06-17 Sophia Borowka , Gudrun Heinrich

We calculate a class of one-loop six-point amplitudes in the Yukawa model. The construction of multi-particle amplitudes is done in the string inspired formalism and compared to the Feynman diagrammatic approach. We show that there exists a…

High Energy Physics - Phenomenology · Physics 2009-11-07 T. Binoth , J. P. Guillet , G. Heinrich , C. Schubert

Recent electroweak two-loop corrections in the Minimal Supersymmetric Standard Model (MSSM) are reviewed. They have been obtained with the help of the programs FeynArts and TwoCalc, making use of the recently completed MSSM model file for…

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Heinemeyer

This is the manual of the first version of QEDtool, an object-oriented Python package that performs numerical quantum electrodynamics calculations, with focus on full state reconstruction in the internal degrees of freedom, correlations and…

High Energy Physics - Theory · Physics 2026-04-07 Jesse Smeets , Preslav Asenov , Alessio Serafini

The rational parts of 5-gluon one-loop amplitudes are computed by using the newly developed method for computing the rational parts directly from Feynman integrals. We found complete agreement with the previously well-known results of Bern,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Xun Su , Zhi-Guang Xiao , Gang Yang , Chuan-Jie Zhu

The state-of-the-art in current two-loop QCD amplitude calculations is at five-particle scattering. Computing two-loop six-particle processes requires knowledge of the corresponding one-loop amplitudes to higher orders in the dimensional…

High Energy Physics - Theory · Physics 2023-02-08 Johannes M. Henn , Antonela Matijašić , Julian Miczajka

A scheme for systematically achieving accurate numerical evaluation of multi-loop Feynman diagrams is developed. This shows the feasibility of a project aimed to produce a complete calculation for two-loop predictions in the Standard Model.…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Passarino

A way to efficiently compute helicity amplitudes for arbitrary tree-level scattering processes in QCD is presented. The scattering amplitude is evaluated recursively through a set of Dyson-Schwinger equations. The computational cost of this…

High Energy Physics - Phenomenology · Physics 2009-11-11 Costas G. Papadopoulos , Malgorzata Worek

The version 2.0 of the program SecDec is described, which can be used for the extraction of poles within dimensional regularisation from multi-loop integrals as well as phase space integrals. The numerical evaluation of the resulting finite…

High Energy Physics - Phenomenology · Physics 2012-06-25 Sophia Borowka , Jonathon Carter , Gudrun Heinrich

We present a new method for computing complete one-loop amplitudes, including their rational parts, in non-supersymmetric gauge theory. This method merges the unitarity method with on-shell recursion relations. It systematizes a…

High Energy Physics - Phenomenology · Physics 2010-11-15 Zvi Bern , Lance J. Dixon , David A. Kosower

We report on the two-loop amplitude computation for the mixed QCD-electroweak corrections to the process $gg \to Hg$, with exact dependence on the electroweak boson masses. This amplitude has been employed in the computation of…

High Energy Physics - Phenomenology · Physics 2022-05-11 Matteo Becchetti , Francesco Moriello , Armin Schweitzer

aITALC, a new tool for automating loop calculations in high energy physics, is described. The package creates Fortran code for two-fermion scattering processes automatically, starting from the generation and analysis of the Feynman graphs.…

High Energy Physics - Phenomenology · Physics 2009-11-10 Alejandro Lorca , Tord Riemann

We present the complete set of Feynman rules producing the rational terms of kind R_2 needed to perform any 1-loop calculation in the Electroweak Standard Model. Our results are given both in the 't Hooft-Veltman and in the Four Dimensional…

High Energy Physics - Phenomenology · Physics 2010-10-28 M. V. Garzelli , I. Malamos , R. Pittau

Starting from the parametric representation of a Feynman diagram, we obtain it's well defined value in dimensional regularisation by changing the integrals over parameters into contour integrals. That way we eventually arrive at a…

High Energy Physics - Phenomenology · Physics 2007-05-23 K. Knecht , H. Verschelde

We develop a method for computing exact one-loop quantum corrections to the energies of static classical backgrounds in renormalizable quantum field theories. We use a continuum density of states formalism to construct a regularized Casimir…

High Energy Physics - Theory · Physics 2009-09-25 N. Graham

In this letter we present a recursive method for computing one-loop off-shell amplitudes in colored quantum field theories. First, we generalize the perturbiner method by recasting the multiparticle currents as generators of off-shell tree…

High Energy Physics - Theory · Physics 2023-03-14 Humberto Gomez , Renann Lipinski Jusinskas , Cristhiam Lopez-Arcos , Alexander Quintero Velez

There is currently a high demand for theoretical predictions for processes at next-to-next-to-leading order (NNLO) and beyond, mainly due to the large amount of data which has already been collected at LHC. This requires practical methods…

High Energy Physics - Theory · Physics 2022-07-06 B. Z. Felippe , A. P. Baêta Scarpelli , A. R. Vieira , J. C. C. Felipe

We review the recently developed bootstrap method for the computation of high-multiplicity QCD amplitudes at one loop. We illustrate the general algorithm step by step with a six-point example. The method combines (generalized) unitarity…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger

I give a basic introduction to precision electroweak analysis, beginning with calculation at tree-level which most simply illustrates the procedure. I then work out the formalism for one-loop corrections to the vector boson self energies…

High Energy Physics - Phenomenology · Physics 2007-05-23 James D. Wells