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We determine the three-loop form factor parameterising the amplitude for the production of an off-shell Higgs boson in gluon fusion in QCD with a single massive quark. The result is obtained via a numerical solution of a system of…

High Energy Physics - Phenomenology · Physics 2020-06-04 M. Czakon , M. Niggetiedt

We present the color planar and complete light quark QCD contributions to the three loop heavy quark form factors in the case of vector, axial-vector, scalar and pseudo-scalar currents. We evaluate the master integrals applying a new method…

High Energy Physics - Phenomenology · Physics 2018-07-18 Jakob Ablinger , Johannes Bluemlein , Peter Marquard , Narayan Rana , Carsten Schneider

We study the photon-quark-quark and Higgs-gluon-gluon form factors for on-shell massless quarks and gluons in perturbative QCD. Previous third-order results for the quark case are extended by calculating the fermion-loop contributions up to…

High Energy Physics - Phenomenology · Physics 2010-04-05 S. Moch , J. A. M. Vermaseren , A. Vogt

We describe in detail the implementation of a systematic perturbative approach to observables in the QCD gradient-flow formalism. This includes a collection of all relevant Feynman rules of the five-dimensional field theory and the…

High Energy Physics - Lattice · Physics 2022-10-12 Johannes Artz , Robert V. Harlander , Fabian Lange , Tobias Neumann , Mario Prausa

We use the method of differential equations to analytically evaluate all planar three-loop Feynman integrals relevant for form factor calculations involving massive particles. Our results for ninety master integrals at general $q^2$ are…

High Energy Physics - Phenomenology · Physics 2017-02-01 Johannes M. Henn , Alexander V. Smirnov , Vladimir A. Smirnov

In this review some recent multi-loop results obtained in the framework of perturbative Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED) are discussed. After reviewing the most advanced techniques used for the computation of…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Steinhauser

We compute the three-loop non-singlet corrections to the photon-quark form factors taking into account the full dependence on the virtuality of the photon and the quark mass. We combine the method of differential equations in an effective…

High Energy Physics - Phenomenology · Physics 2022-05-11 Matteo Fael , Fabian Lange , Kay Schoenwald , Matthias Steinhauser

We summarize the results for the master integrals of the three-loop quark and gluon form factor in massless QCD. Working in dimensional regularization we extract poles up to 1/epsilon^6. The computational techniques involve, among others,…

High Energy Physics - Phenomenology · Physics 2010-01-20 T. Huber

We give explicit formulae for the O(eps) and O(eps^2) contributions to the unrenormalised three loop QCD corrections to quark and gluon form factors. These contributions have at most transcendentality weight eight. The O(eps) terms of the…

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

We evaluate, exactly in d, the master integrals contributing to massless three-loop QCD form factors. The calculation is based on a combination of a method recently suggested by one of the authors (R.L.) with other techniques: sector…

High Energy Physics - Phenomenology · Physics 2015-03-13 R. N. Lee , A. V. Smirnov , V. A. Smirnov

We compute the fermionic contribution to the photon-quark form factor to four-loop order in QCD in the planar limit in analytic form. From the divergent part of the latter the cusp and collinear anomalous dimensions are extracted. Results…

High Energy Physics - Phenomenology · Physics 2016-04-19 Johannes M. Henn , Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons to three-loop order within massless perturbative Quantum Chromodynamics. These results provide building blocks for…

High Energy Physics - Phenomenology · Physics 2009-06-30 P. A. Baikov , K. G. Chetyrkin , A. V. Smirnov , V. A. Smirnov , M. Steinhauser

We review the electromagnetic form factor of heavy quarks with emphasis on the QCD radiative corrections at two-loop order in the perturbative expansion. We discuss important properties of the heavy-quark form factor such as its…

High Energy Physics - Phenomenology · Physics 2010-05-12 S. Moch

We analytically compute all four-loop QCD corrections to the photon-quark and Higgs-gluon form factors involving a closed massless fermion loop. Our calculation of non-planar vertex integrals confirms a previous conjecture for the…

We present closed analytic expressions of the electromagnetic vertex form factors for heavy quarks at the two-loop level in QCD for arbitrary momentum transfer. The calculation is carried out in dimensional regularization. The electric and…

High Energy Physics - Phenomenology · Physics 2010-04-05 W. Bernreuther , R. Bonciani , T. Gehrmann , R. Heinesch , T. Leineweber , P. Mastrolia , E. Remiddi

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 the photon-quark and Higgs-gluon form factors to four-loop order within massless perturbative Quantum Chromodynamics. Our results constitute ready-to-use building blocks for N${}^4$LO cross sections for Drell-Yan processes and…

I discuss recent applications of QCD light-cone sum rules to various form factors of pseudoscalar mesons. In this approach both soft and hard contributions to the form factors are taken into account. Combining QCD calculation with the…

High Energy Physics - Phenomenology · Physics 2010-02-16 A. Khodjamirian

We calculate the form factors for the heavy-to-light transitions $B\rightarrow \pi,K $ by means of QCD sum rules using $\pi$ and $K$ light-cone wave functions. Higher twist contributions as well as gluonic corrections are taken into…

High Energy Physics - Phenomenology · Physics 2019-08-15 V. M. Belyaev , A. Khodjamirian , R. Rückl

We consider the virtual corrections to Higgs boson pair production at next-to-next-to-leading order, in the large top quark mass limit. We compute five expansion terms for the box-type form factors and eight expansion terms for the triangle…

High Energy Physics - Phenomenology · Physics 2020-01-08 Joshua Davies , Matthias Steinhauser