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An algorithm for the reduction of one-loop n-point tensor integrals to basic integrals is proposed. We transform tensor integrals to scalar integrals with shifted dimension and reduce these by recurrence relations to integrals in generic…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Fleischer , F. Jegerlehner , O. V. Tarasov

In this presentation, we review the general features of integrand-reduction techniques, with a particular focus on their generalization beyond one loop. We start with a brief discussion of the one-loop scenario, a case in which…

High Energy Physics - Phenomenology · Physics 2016-08-01 Giovanni Ossola

The method for functional reduction of Feynman integrals, proposed by the author, is used to calculate one-loop integrals corresponding to diagrams with four external lines. The integrals that emerge from amplitudes for the scattering of…

High Energy Physics - Phenomenology · Physics 2023-07-12 O. V. Tarasov

We compute the two-loop QCD helicity amplitudes for the process e^+e^- --> q bar{q} g. The amplitudes are extracted in a scheme-independent manner from the coefficients appearing in the general tensorial structure for this process. The…

High Energy Physics - Phenomenology · Physics 2010-04-06 L. W. Garland , T. Gehrmann , E. W. N. Glover , A. Koukoutsakis , E. Remiddi

We present a generally applicable reduction formalism which makes it possible to express an arbitrary tensor and scalar one-loop Feynman integral, with N external lines and massless propagators, in terms of a basic set of eight fundamental…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Duplancic , B. Nizic

A method for calculating loop amplitudes at the multiboson threshold is presented, based on Feynman-diagram techniques. We explicitly calculate the one-loop amplitudes in both $\phi^4$-symmetric and broken symmetry cases, using dimensional…

High Energy Physics - Phenomenology · Physics 2009-10-22 E. N. Argyres , Ronald H. P. Kleiss , Costas G. Papadopoulos

We combine the six-dimensional helicity formalism of Cheung and O'Connell with D-dimensional generalized unitarity to obtain a new formalism for computing one-loop amplitudes in dimensionally regularized QCD. With this procedure, we…

High Energy Physics - Phenomenology · Physics 2013-05-29 Scott Davies

A computer program has been developed which generates Feynman graphs automatically for scattering and decay processes in non-Abelian gauge theory of high-energy physics. A new acceleration method is presented for both generating and…

High Energy Physics - Theory · Physics 2009-10-28 Toshiaki Kaneko

Some of the difficulties faced when calculating multi-loop amplitudes with several mass scales are reviewed. We then focus on one particular difficulty, the evaluation of the Feynman integrals, and introduce the program pySecDec which can…

High Energy Physics - Phenomenology · Physics 2018-06-08 S. P. Jones , B. Ruijl

A method to efficiently compute, in a automatic way, helicity amplitudes for arbitrary scattering processes at leading order in the Standard Model is presented. The scattering amplitude is evaluated recursively through a set of…

High Energy Physics - Phenomenology · Physics 2007-05-23 Costas G. Papadopoulos , Malgorzata Worek

Version 2 of 'carlomat', a program for automatic computation of the lowest order cross sections of multiparticle reactions, is described. The substantial modifications with respect to version 1 of the program include: generation of a single…

High Energy Physics - Phenomenology · Physics 2015-06-16 Karol Kolodziej

We discuss two-loop leading and angular-dependent next-to-leading logarithmic electroweak virtual corrections to arbitrary processes at energies above the electroweak scale. The relevant Feynman diagrams involving soft-collinear gauge…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ansgar Denner , Michael Melles , Stefano Pozzorini

The FDC is a general-purpose program package for Feynman Diagram Calculation. We outline previous successes in calculations and focus on its recent progress about automatic deduction the Feynman rules for first principle model, especially…

High Energy Physics - Phenomenology · Physics 2009-11-10 Jian-Xiong Wang

We present GLEAM (Galaxy Line Emission & Absorption Modeling), a Python tool for fitting Gaussian models to emission and absorption lines in large samples of 1D extragalactic spectra. GLEAM is tailored to work well in batch mode without…

Instrumentation and Methods for Astrophysics · Physics 2021-03-08 Andra Stroe , Victor-Nicolae Savu

Gaussian Processes (GPs) are widely used tools in statistics, machine learning, robotics, computer vision, and scientific computation. However, despite their popularity, they can be difficult to apply; all but the simplest classification or…

Machine Learning · Computer Science 2016-01-06 Ulrich Schaechtle , Ben Zinberg , Alexey Radul , Kostas Stathis , Vikash K. Mansinghka

SOFTSUSY is a program which accurately calculates the spectrum of superparticles in the CP-conserving Minimal Supersymmetric Standard Model (MSSM), with a full flavour mixing structure. The program solves the renormalisation group equations…

High Energy Physics - Phenomenology · Physics 2012-07-31 B. C. Allanach

In this work we give a detailed description of a method for the calculation of QCD corrections to electroweak processes in dimensional regularization that does not require any definition of the gamma_5 matrix in d dimensions. This method…

High Energy Physics - Phenomenology · Physics 2009-10-28 Giancarlo Cella , Giuseppe Curci , Giulia Ricciardi , Andrea Vicere'

Numerical calculation of two-loop electroweak corrections to the muon anomalous magnetic moment ($g$-2) is done based on, on shell renormalization scheme (OS) and free quark model (FQM). The GRACE-FORM system is used to generate Feynman…

High Energy Physics - Phenomenology · Physics 2019-04-17 Tadashi Ishikawa , Nobuya Nakazawa , Yoshiaki Yasui

By carefully analyzing the relations between operator methods and the discretized and continuum path integral formulations of quantum-mechanical systems, we have found the correct Feynman rules for one-dimensional path integrals in curved…

High Energy Physics - Theory · Physics 2009-10-28 Jan de Boer , Bas Peeters , Kostas Skenderis , Peter van Nieuwenhuizen

We study Feynman rules for the rational part $R$ of the Standard Model amplitudes at one-loop level in the 't Hooft-Veltman $\gamma_5$ scheme. Comparing our results for quantum chromodynamics and electroweak 1-loop amplitudes with that…

High Energy Physics - Phenomenology · Physics 2015-05-28 Hua-Sheng Shao , Yu-Jie Zhang , Kuang-Ta Chao