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I have evaluated up to 1100 digits of precision the contribution of the 891 4-loop Feynman diagrams contributing to the electron $g$-$2$ in QED. The total mass-independent 4-loop contribution is $ a_e =…

High Energy Physics - Phenomenology · Physics 2017-08-23 Stefano Laporta

We present the values of the complete set of planar four-point Master Integrals needed for massive Bhabha scattering in the limit of fixed angle and high energy at the two-loop level. The integrals have been calculated using direct…

High Energy Physics - Phenomenology · Physics 2010-04-05 M. Czakon , J. Gluza , T. Riemann

We present the two-loop master integrals relevant to the ${\mathcal O}(\alpha \alpha_s)$-corrections to the decay $H \rightarrow b \bar{b}$ through a $H t \bar{t}$-coupling. We keep the full dependence on the heavy particle masses, but…

High Energy Physics - Phenomenology · Physics 2019-06-26 Ekta Chaubey , Stefan Weinzierl

We overview the general status of higher order corrections to Bhabha scattering and review recent progress in the determination of the two-loop virtual corrections. Quite recently, they were derived from combining a massless calculation and…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Czakon , J. Gluza , T. Riemann

We present the Master Integrals needed for the calculation of the two-loop QCD corrections to the forward-backward asymmetry of a quark-antiquark pair produced in electron-positron annihilation events. The abelian diagrams entering in the…

High Energy Physics - Phenomenology · Physics 2009-11-10 R. Bonciani , P. Mastrolia , E. Remiddi

We present the program BOKASUN for fast and precise evaluation of the Master Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the internal masses and the external four-momentum. We use a combination of two…

High Energy Physics - Phenomenology · Physics 2009-11-13 Michele Caffo , Henryk Czyz , Michal Gunia , Ettore Remiddi

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

The master differential equations in the external square momentum p^2 for the master integrals of the two-loop sunrise graph, in n-continuous dimensions and for arbitrary values of the internal masses, are derived. The equations are then…

High Energy Physics - Theory · Physics 2010-04-06 M. Caffo , H. Czyz , S. Laporta , E. Remiddi

The 4-th order Runge-Kutta method in the complex plane is proposed for numerically advancing the solutions of a system of first order differential equations in one external invariant satisfied by the master integrals related to a Feynman…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Caffo , H. Czyz , E. Remiddi

We present an efficient approach to evaluate two-center two-electron integrals with exponential functions and with an arbitrary polynomial in electron-nucleus and electron-electron distances. We show that the master integral with the single…

Chemical Physics · Physics 2009-09-29 Krzysztof Pachucki

We consider Feynman integrals with algebraic leading singularities and total differentials in $\epsilon\,\mathrm{d}\ln$ form. We show for the first time that it is possible to evaluate integrals with singularities involving unrationalizable…

High Energy Physics - Theory · Physics 2020-08-18 Matthias Heller , Andreas von Manteuffel , Robert M. Schabinger

We consider the case of a two-loop five-point pentagon-box integral configuration with one internal massive propagator that contributes to top-quark pair production in association with a jet at hadron colliders. We construct the system of…

High Energy Physics - Phenomenology · Physics 2023-03-31 Simon Badger , Matteo Becchetti , Ekta Chaubey , Robin Marzucca

The three-loop master integrals for ladder-box diagrams with one massive leg are computed from an eighty-five by eighty-five system of differential equations, solved by means of Magnus exponential. The results of the considered box-type…

High Energy Physics - Phenomenology · Physics 2015-06-22 Stefano Di Vita , Pierpaolo Mastrolia , Ulrich Schubert , Valery Yundin

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 describe a constructive procedure to separate overlapping infrared divergences in multi-loop integrals. Working with a parametric representation in D=4-2*epsilon dimensions, adequate subtractions lead to a Laurent series in epsilon,…

High Energy Physics - Phenomenology · Physics 2009-10-31 T. Binoth , G. Heinrich

We consider the question about the number of master integrals for a multiloop Feynman diagram. We show that, for a given set of denominators, this number is totally determined by the critical points of the polynomials entering either of the…

High Energy Physics - Phenomenology · Physics 2015-06-17 Roman N. Lee , Andrei A. Pomeransky

All three-loop on-shell QCD Feynman integrals with two masses can be reduced to 27 master integrals. Here we calculate these master integrals, expanded in epsilon, both exactly in the mass ratio and as series in limiting cases.

High Energy Physics - Phenomenology · Physics 2009-12-27 S. Bekavac , A. G. Grozin , D. Seidel , V. A. Smirnov

I study the Feynman integrals needed to compute two-loop self-energy functions for general masses and external momenta. A convenient basis for these functions consists of the four integrals obtained at the end of Tarasov's recurrence…

High Energy Physics - Phenomenology · Physics 2014-11-17 Stephen P. Martin

We introduce in typical examples new methods for the calculation of massive loop integrals appearing in the radiative correction calculations of the Standard Model.

High Energy Physics - Phenomenology · Physics 2011-04-20 Dirk Kreimer

A general one-loop scattering amplitude may be expanded in terms of master integrals. The coefficients of the master integrals can be obtained from tree-level input in a two-step process. First, use known formulas to write the coefficients…

High Energy Physics - Phenomenology · Physics 2009-01-14 Ruth Britto , Bo Feng , Gang Yang