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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 present a new method for the numerical evaluation of loop integrals which is based on the Feynman Tree Theorem. The loop integrals are replaced by phase-space integration over fictitious extra on-shell particles. This integration can be…

High Energy Physics - Phenomenology · Physics 2009-12-18 Wolfgang Kilian , Tobias Kleinschmidt

FEMSIM, a Fortran code, has been developed to simulate the fluctuation electron microscopy signal, the variance, V(k), from a model atomic structure. FEMSIM has been incorporated into a hybrid-reverse Monte Carlo code that combines an…

Materials Science · Physics 2017-02-06 Jason J. Maldonis , Jinwoo Hwang , Paul M. Voyles

The evaluation of higher-loop Feynman integrals is at the core of the quest to reduce the uncertainty of theoretical predictions and match experimental data from the LHC and future colliders. pySecDec is a program to evaluate such integrals…

High Energy Physics - Phenomenology · Physics 2022-03-01 Vitaly Magerya

We apply the differential equation technique to the calculation of the one-loop massless diagram with five onshell legs. Using the reduction to $\epsilon$-form, we manage to obtain a simple one-fold integral representation exact in…

High Energy Physics - Phenomenology · Physics 2016-03-23 Mikhail G. Kozlov , Roman N. Lee

The various sources of Rational Terms contributing to the one-loop amplitudes are critically discussed. We show that the terms originating from the generic (n-4)-dimensional structure of the numerator of the one-loop amplitude can be…

High Energy Physics - Phenomenology · Physics 2008-11-26 Giovanni Ossola , Costas G. Papadopoulos , Roberto Pittau

We present a set of algebraic functions for evaluating the coefficients of the scalar integral basis of a general one-loop amplitude. The functions are derived from unitarity cuts, but the complete cut-integral procedure has been carried…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ruth Britto , Bo Feng

We present a method of computing any one-loop integral in lattice perturbation theory by systematically expanding around its continuum limit. At any order in the expansion in the lattice spacing, the result can be written as a sum of…

High Energy Physics - Phenomenology · Physics 2009-11-07 Thomas Becher , Kirill Melnikov

We present Open Multi-Processing (OpenMP) version of Fortran 90 programs for solving the Gross-Pitaevskii (GP) equation for a Bose-Einstein condensate in one, two, and three spatial dimensions, optimized for use with GNU and Intel…

Various implementations of the Unitarity method have been developed to compute one-loop amplitudes in gauge theories. In this paper we present an implementation which uses canonical forms to generate the rational coefficients of the basis…

High Energy Physics - Phenomenology · Physics 2009-11-24 David C. Dunbar , Warren B. Perkins , Edmund Warrick

A framework to represent and compute two-loop $N$-point Feynman diagrams as double-integrals is discussed. The integrands are 'generalised one-loop type" multi-point functions multiplied by simple weighting factors. The final integrations…

High Energy Physics - Phenomenology · Physics 2020-04-15 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

We discuss an algorithm for the numerical evaluation of NLO multiparton processes. We focus hereby on the virtual part of the NLO calculation, i.e. on evaluating the one-loop integration numerically. We employ and extend the ideas of the…

High Energy Physics - Phenomenology · Physics 2012-09-14 S. Becker , D. Goetz , C. Reuschle , C. Schwan , S. Weinzierl

We describe a new method for the automated construction of one-loop amplitudes based on the open-loop algorithm, where various operations are performed on-the-fly while constructing the integrand. In particular, an on-the-fly reduction…

High Energy Physics - Phenomenology · Physics 2018-01-12 Federico Buccioni , Stefano Pozzorini , Max Zoller

We present an efficient graphical approach to construct projectors for the tensor reduction of multi-loop Feynman integrals with both Lorentz and spinor indices in $D$ dimensions. An ansatz for the projectors is constructed making use of…

High Energy Physics - Phenomenology · Physics 2025-04-29 Jae Goode , Franz Herzog , Anthony Kennedy , Sam Teale , Jos Vermaseren

We have developed PROGRAPE-1 (PROgrammable GRAPE-1), a programmable multi-purpose computer for many-body simulations. The main difference between PROGRAPE-1 and "traditional" GRAPE systems is that the former uses FPGA (Field Programmable…

Astrophysics · Physics 2015-06-24 Tsuyoshi Hamada , Toshiyuki Fukushige , Atsushi Kawai , Junichiro Makino

We set up a new, flexible approach for the tensor reduction of one-loop Feynman integrals. The 5-point tensor integrals up to rank R=5 are expressed by 4-point tensor integrals of rank R-1, such that the appearance of the inverse 5-point…

High Energy Physics - Phenomenology · Physics 2011-04-22 J. Fleischer , T. Riemann

A comprehensive study is performed of two-loop Feynman diagrams with three external legs which, due to the exchange of massless gauge-bosons, give raise to infrared and collinear divergencies. Their relevance in assembling realistic…

High Energy Physics - Phenomenology · Physics 2009-11-11 Giampiero Passarino , Sandro Uccirati

In this paper we present Open Multi-Processing (OpenMP) Fortran 90/95 versions of previously published numerical programs for solving the dipolar Gross-Pitaevskii (GP) equation including the contact interaction in one, two and three spatial…

Quantum Gases · Physics 2023-02-08 Luis E. Young-S. , Paulsamy Muruganandam , Antun Balaž , Sadhan K. Adhikari

We present an extension of the spinor integration formalism of one loop amplitudes from the double-cut to the single-cut case. This technique can be applied for the computation of the tadpole coefficients. Moreover we describe an off-shell…

High Energy Physics - Phenomenology · Physics 2012-02-14 Ruth Britto , Edoardo Mirabella

We calculate the three-loop master integrals contributing to the three-loop five-point amplitude on the special Coulomb branch of $\mathcal{N}=4$ SYM theory. For the genuine pentagon integrals, we follow the approach of Ref. [JHEP 12 (2025)…

High Energy Physics - Theory · Physics 2026-05-19 Andrei V. Belitsky , Leonid V. Bork , Roman N. Lee , Andrei I. Onishchenko , Vladimir A. Smirnov
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