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Higher order calculations in perturbative Quantum Field Theories often produce coupled linear systems of differential equations which factorize to first order. Here we present an algorithm to solve such systems in terms of iterated…

High Energy Physics - Phenomenology · Physics 2020-08-26 J. Ablinger , J. Blümlein , P. Marquard , N. Rana , C. Schneider

We compute the master integrals for massless two-loop vertex graphs with three off-shell legs. These master integrals are relevant for the QCD corrections to H to V*V* (where V = W, Z) and for two-loop studies of the triple gluon (and…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. G. Birthwright , E. W. N. Glover , P. Marquard

In this contribution we provide further details to the recent calculation of QCD corrections to massive three-loop form factors presented in Ref. [1].

High Energy Physics - Phenomenology · Physics 2018-07-26 Roman N. Lee , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We consider two-loop planar contributions to a three-body form factor at the next-to-leading power in the high-energy limit, where the masses of external particles are much smaller than their energies. The calculation is performed by…

High Energy Physics - Phenomenology · Physics 2025-05-21 Yishuai Guo , Zhi-Feng Liu , Mingming Lu , Tianya Xia , Li Lin Yang

We present numerical results which are needed to evaluate all non-trivial master integrals for four-loop massless propagators, confirming the recent analytic results of[1]and evaluating an extra order in $\ep$ expansion for each master…

High Energy Physics - Phenomenology · Physics 2014-11-20 A. V. Smirnov , M. Tentyukov

We present analytic results for three-loop fermionic corrections to the heavy-light form factors in perturbative quantum chromodynamics. Specifically, we present all light quark contributions and contributions from two heavy quark loops. We…

High Energy Physics - Phenomenology · Physics 2024-07-23 Sudeepan Datta , Narayan Rana

We calculate the four-loop massless QCD corrections with three closed quark lines to quark and gluon form factors. We apply a novel integration by parts algorithm based on modular arithmetic and compute all relevant master integrals for…

High Energy Physics - Phenomenology · Physics 2017-03-01 Andreas von Manteuffel , Robert M. Schabinger

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of…

High Energy Physics - Phenomenology · Physics 2019-09-04 Matteo Becchetti , Roberto Bonciani , Valerio Casconi , Andrea Ferroglia , Simone Lavacca , Andreas von Manteuffel

The non-first-order-factorizable contributions (The terms 'first-order-factorizable contributions' and 'non-first-order-factorizable contributions' have been introduced and discussed in Refs. \cite{Behring:2023rlq,Ablinger:2023ahe}. They…

High Energy Physics - Phenomenology · Physics 2024-05-15 J. Ablinger , A. Behring , J. Blümlein , A. De Freitas , A. von Manteuffel , C. Schneider , K. Schönwald

We report on recent progress in calculating the three loop QCD corrections of the heavy flavor contributions in deep--inelastic scattering and the massive operator matrix elements of the variable flavor number scheme. Notably we deal with…

High Energy Physics - Phenomenology · Physics 2023-06-30 J. Ablinger , A. Behring , J. Blümlein , A. De Freitas , A. Goedicke , A. von Manteuffel , C. Schneider , K. Schönwald

We present the calculation of the master integrals needed for the two-loop QCDxEW corrections to $ q + \bar{q} \to l^- + l^+$ and $ q + \bar{q}' \to l^- + \overline{\nu} \, , $ for massless external particles. We treat W and Z bosons as…

High Energy Physics - Phenomenology · Physics 2016-10-12 Roberto Bonciani , Stefano Di Vita , Pierpaolo Mastrolia , Ulrich Schubert

We compute the color-planar and complete light quark non-singlet contributions to the heavy quark form factors in the case of the axialvector, scalar and pseudoscalar currents at three loops in perturbative QCD. We evaluate the master…

High Energy Physics - Phenomenology · Physics 2018-08-01 J. Ablinger , J. Blümlein , P. Marquard , N. Rana , C. Schneider

We compute all master integrals for massless three-loop four-particle scattering amplitudes required for processes like di-jet or di-photon production at the LHC. We present our result in terms of a Laurent expansion of the integrals in the…

High Energy Physics - Phenomenology · Physics 2020-05-20 Johannes Henn , Bernhard Mistlberger , Vladimir A. Smirnov , Pascal Wasser

We compute the two-loop corrections to the massless quark form factor $\gamma^* \to q\bar q$ and gluon form factor $H\to gg$ to all orders in the dimensional regularisation parameter $\epsilon=(4-d)/2$. The two-loop contributions to the…

High Energy Physics - Phenomenology · Physics 2021-11-04 T. Gehrmann , T. Huber , D. Maitre

An analytical expression for the three-loop form factors for $ggH$ and $\gamma\gamma H$ is derived for the contributions which involve massless quark loops. The result is expressed in terms of harmonic polylogarithms. It fully agrees with…

High Energy Physics - Phenomenology · Physics 2020-07-23 Robert V. Harlander , Mario Prausa , Johann Usovitsch

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 consider Quantum Chromodynamics with external vector, axial-vector, scalar and pseudo-scalar currents and compute three-loop corrections to the corresponding vertex function taking into account massive quarks. We consider all non-singlet…

High Energy Physics - Phenomenology · Physics 2022-09-14 Matteo Fael , Fabian Lange , Kay Schönwald , Matthias Steinhauser

Applications of a method recently suggested by one of the authors (R.L.) are presented. This method is based on the use of dimensional recurrence relations and analytic properties of Feynman integrals as functions of the parameter of…

High Energy Physics - Phenomenology · Physics 2015-03-17 Roman N. Lee , Alexander V. Smirnov , Vladimir A. Smirnov

We describe the calculation of the three-loop QCD corrections to quark and gluon form factors. The relevant three-loop Feynman diagrams are evaluated and the resulting three-loop Feynman integrals are reduced to a small set of known master…

High Energy Physics - Phenomenology · Physics 2023-11-15 T. Gehrmann , E. W. N. Glover , T. Huber , N. Ikizlerli , C. Studerus

In the paper, we obtain an expression for a two-loop master-diagram by using the Mellin$-$Barnes transformation. In the two-dimensional case we managed to factorize the answer and write it as a bilinear combination of hypergeometric…

High Energy Physics - Theory · Physics 2023-10-05 S. E. Derkachev , A. V. Ivanov , L. A. Shumilov