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We present the calculation of massless two-loop Master Integrals relevant to five-point amplitudes with one off-shell external leg and derive the complete set of planar Master Integrals with five on-mass-shell legs, that contribute to many…

High Energy Physics - Phenomenology · Physics 2016-05-04 Costas G. Papadopoulos , Damiano Tommasini , Christopher Wever

We study real-time scalar $\phi^4$-theory in 2+1 dimensions near criticality. Specifically, we compute the single-particle spectral function and that of the $s$-channel four-point function in and outside the scaling regime. The computation…

High Energy Physics - Theory · Physics 2025-06-12 Konrad Kockler , Jan M. Pawlowski , Jonas Wessely

We propose a new method to calculate the 4-dimensional divergent integrals. By calculating the one loop integral as an example, the regularization of the integrals in 3-dimension momentum space are given in details. We find that the new…

High Energy Physics - Theory · Physics 2007-05-23 Liang-gang Liu , Xiang-Qian Luo , Wei Chen

We present a program that implements the OPP reduction method to extract the coefficients of the one-loop scalar integrals from a user defined (sub)-amplitude or Feynman Diagram, as well as the rational terms coming from the 4-dimensional…

High Energy Physics - Phenomenology · Physics 2011-05-05 Giovanni Ossola , Costas G. Papadopoulos , Roberto Pittau

A method to isolate the poles of dimensionally regulated multi-loop integrals and to calculate the pole coefficients numerically is extended to be applicable to phase space integrals as well.

High Energy Physics - Phenomenology · Physics 2008-12-30 G. Heinrich

A four-way coupling scheme for the direct numerical simulation of particle-laden flows is developed and analyzed. It employs a novel adaptive multi-relaxation time lattice Boltzmann method to simulate the fluid phase efficiently. The…

Computational Physics · Physics 2020-03-04 Christoph Rettinger , Ulrich Rüde

We propose a method to expand correlation functions with respect to the spatial components of external momenta. From the coefficients of the expansion it is possible to extract Lorentz-invariant form factors at zero spatial momentum…

High Energy Physics - Lattice · Physics 2015-06-11 G. M. de Divitiis , R. Petronzio , N. Tantalo

We formulate a set of general rules for computing $d$-dimensional four-point global conformal blocks of operators in arbitrary Lorentz representations in the context of the embedding space operator product expansion formalism…

High Energy Physics - Theory · Physics 2021-11-24 Jean-François Fortin , Wen-Jie Ma , Valentina Prilepina , Witold Skiba

A new Monte-Carlo method for solving linear parabolic partial differential equations is presented. Since, in this new scheme, the particles are followed backward in time, it provides great flexibility in choosing critical points in…

Numerical Analysis · Mathematics 2025-10-20 Johan Carlsson

We present Path Integral Monte Carlo C code for calculation of quantum mechanical transition amplitudes for 1D models. The SPEEDUP C code is based on the use of higher-order short-time effective actions and implemented to the maximal order…

We present a new Fortran library to evaluate all harmonic polylogarithms up to weight four numerically for any complex argument. The algorithm is based on a reduction of harmonic polylogarithms up to weight four to a minimal set of basis…

High Energy Physics - Phenomenology · Physics 2011-06-29 Stephan Buehler , Claude Duhr

We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding…

High Energy Physics - Phenomenology · Physics 2008-11-26 Darren Forde

We calculate the light cone wave functions for a virtual photon to split into quark-antiquark states, including for the first time quark masses at one loop accuracy. These wave functions can be used to calculate cross sections for several…

High Energy Physics - Phenomenology · Physics 2022-08-31 G. Beuf , T. Lappi , R. Paatelainen

A numerical program is presented which facilitates a computation pertaining to the full set of one-gluon loop diagrams (including ghost loop contributions), with M attached external gluon lines in all possible ways. The feasibility of such…

High Energy Physics - Theory · Physics 2009-11-11 A. S. Kapoyannis , A. I. Karanikas , C. N. Ktorides

We present a subtraction scheme for eliminating the ultraviolet, soft, and collinear divergences in the numerical calculation of an arbitrary one-loop QCD amplitude with an arbitrary number of external legs. The subtractions consist of…

High Energy Physics - Phenomenology · Physics 2009-11-10 Zoltan Nagy , Davison E. Soper

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 calculation of two-point three-loop functions with an arbitrary number of massive propagators and one large external momentum. The relevant subdiagrams are generated automatically. The resulting massless two-point integrals…

High Energy Physics - Phenomenology · Physics 2011-04-15 K. G. Chetyrkin , R. Harlander , J. H. Kuehn , M. Steinhauser

A method of functional reduction for the dimensionally regularized one-loop Feynman integrals with massive propagators is described in detail. The method is based on a repeated application of the functional relations proposed by the author.…

High Energy Physics - Phenomenology · Physics 2022-07-13 O. V. Tarasov

The calculation of massive 2--loop operator matrix elements, required for the higher order Wilson coefficients for heavy flavor production in deeply inelastic scattering, leads to new types of multiple infinite sums over harmonic sums and…

Mathematical Physics · Physics 2008-12-18 I. Bierenbaum , J. Blümlein , S. Klein , C. Schneider

One-loop amplitudes of gluons in N=4 gauge theory can be written as linear combinations of known scalar box integrals with coefficients that are rational functions. In this paper we show how to use generalized unitarity to basically read…

High Energy Physics - Theory · Physics 2009-11-10 Ruth Britto , Freddy Cachazo , Bo Feng
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