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We present the calculation of the mixed two-loop QCD/electroweak corrections to hadronic W boson decays within the Standard Model. The optical theorem is applied to the W boson two-point function. The multi-scale integrals are computed with…

High Energy Physics - Phenomenology · Physics 2015-12-01 Dominik Kara

We perform a two-loop calculation in Light Cone Perturbation Theory (LCPT) to evaluate the next-to-leading order nonsinglet splitting function. Our calculation demonstrates the methodology and feasibility of performing higher order…

High Energy Physics - Phenomenology · Physics 2026-01-16 Tuomas Lappi , Risto Paatelainen , Mikko Seppälä

We present the bare one-, two-, and three-loop form factors in massless Quantum Chromodynamics as linear combinations of finite master integrals. Using symbolic integration, we compute their $\epsilon$ expansions and thereby reproduce all…

High Energy Physics - Phenomenology · Physics 2016-08-30 Andreas von Manteuffel , Erik Panzer , Robert M. Schabinger

In two-dimensional models of critical non-intersecting loops, there are $\ell$-leg fields that insert $\ell\in\mathbb{N}^*$ open loop segments, and diagonal fields that change the weights of closed loops. We conjecture an exact formula for…

Mathematical Physics · Physics 2026-05-06 Jesper Lykke Jacobsen , Rongvoram Nivesvivat , Sylvain Ribault , Paul Roux

An efficient method to calculate tadpole diagrams is proposed. Its capability is demonstrated by analytically evaluating two four-loop tadpole diagrams of current interest in the literature, including their $O(\epsilon)$ terms in…

High Energy Physics - Phenomenology · Physics 2009-11-11 Bernd A. Kniehl , Anatoly V. Kotikov

We compute the three-loop QCD corrections to the massive quark-anti-quark-photon form factors $F_1$ and $F_2$ in the large-$N_c$ limit. The analytic results are expressed in terms of Goncharov polylogarithms. This allows for a…

High Energy Physics - Phenomenology · Physics 2017-03-08 Johannes Henn , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We compute three-loop corrections of $\mathcal{O}(\alpha_{s}^3)$ to form factors with one massive and one massless quark coupling to an external vector, axialvector, scalar, pseudoscalar, or tensor current. We obtain analytic results for…

High Energy Physics - Phenomenology · Physics 2024-09-24 Matteo Fael , Tobias Huber , Fabian Lange , Jakob Müller , Kay Schönwald , Matthias Steinhauser

We find general solutions for the dimensionally regularised scalar one loop three-point and four-point functions with one heavy quark propagator. The scalar one-point function vanishes, while the expression for the two-point function has…

High Energy Physics - Phenomenology · Physics 2009-01-07 J. Zupan

It is shown that the two-loop four-point functions are similar in structure to the three-point two-loop functions for all mass cases and topologies. The result is derived by using a rotation to a (+,-,-,+) signature without spoiling…

High Energy Physics - Phenomenology · Physics 2009-10-28 Dirk Kreimer

One-loop amplitudes may be expanded in a basis of scalar integrals multiplied by rational coefficients. We relate the coefficient of the one-point integral to the coefficients of higher-point integrals, by considering the effects of…

High Energy Physics - Theory · Physics 2011-01-18 Ruth Britto , Bo Feng

We calculate all contributions $\propto T_F$ to the polarized three-loop anomalous dimensions in the M-scheme using massive operator matrix elements and compare to results in the literature. This includes the complete anomalous dimensions…

High Energy Physics - Phenomenology · Physics 2019-09-25 A. Behring , J. Blümlein , A. De Freitas , A. Goedicke , S. Klein , A. von Manteuffel , C. Schneider , K. Schönwald

We calculate three-point functions of two protected operators and one twist-two operator with arbitrary even spin j in N=4 SYM theory to one-loop order. In order to carry out the calculations we project the indices of the spin j operator to…

High Energy Physics - Theory · Physics 2015-06-05 Jan Plefka , Konstantin Wiegandt

This article is the first of a series of three presenting an alternative method to compute the one-loop scalar integrals. This novel method enjoys a couple of interesting features as compared with the method closely following 't Hooft and…

High Energy Physics - Phenomenology · Physics 2020-02-13 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

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

Hard spin-independent three-loop radiative contributions to energy levels in positronium generated by the two-photon-exchange diagrams with one-loop radiative insertions in the fermion lines and exchanged photons are calculated. This is a…

High Energy Physics - Phenomenology · Physics 2022-06-15 Michael I. Eides , Valery A. Shelyuto

We compute the full set of two-loop Feynman integrals appearing in massless two-loop four-point functions with two off-shell legs with the same invariant mass. These integrals allow to determine the two-loop corrections to the amplitudes…

High Energy Physics - Phenomenology · Physics 2014-06-13 Thomas Gehrmann , Andreas von Manteuffel , Lorenzo Tancredi , Erich Weihs

We report on the three-loop unpolarized and polarized massive operator matrix elements, with single- and two-mass corrections, and the associated deep-inelastic massive Wilson coefficients in the region $Q^2 \gg m_Q^2$, the calculation of…

High Energy Physics - Phenomenology · Physics 2026-02-12 J. Ablinger , A. Behring , J. Blümlein , A. De Freitas , A. von Manteuffel , C. Schneider , K. Schönwald

A method to calculate two-loop self-energy diagrams of the Standard Model is demonstrated. A direct physical application is the calculation of the two-loop electroweak contribution to the anomalous magnetic moment of the muon…

High Energy Physics - Phenomenology · Physics 2011-04-15 L. Avdeev , J. Fleischer , M. Yu. Kalmykov , M. Tentyukov

I present a Mathematica package designed for manipulations and evaluations of triple-K integrals and conformal correlation functions in momentum space. Additionally, the program provides tools for evaluation of a large class of 2- and…

High Energy Physics - Theory · Physics 2020-08-26 Adam Bzowski

We explore the properties of two-point cosmic propagators when Perturbation Theory (PT) loop corrections are consistently taken into account. We show in particular how the interpolation scheme proposed in arXiv:1112.3895 can be explicitly…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-15 Francis Bernardeau , Atsushi Taruya , Takahiro Nishimichi