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We compute the three-loop corrections to the quark axial vector form factor in massless QCD, focusing on the pure-singlet contributions where the axial vector current couples to a closed quark loop. Employing the Larin prescription for…

High Energy Physics - Phenomenology · Physics 2021-03-24 T. Gehrmann , A. Primo

Different mathematical methods have been applied to obtain the analytic result for the massless triangle Feynman diagram yielding a sum of four linearly independent hypergeometric functions $F_4$. In this paper I work out the diagram and…

High Energy Physics - Theory · Physics 2008-08-12 Alfredo Takashi Suzuki

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

I obtain identities satisfied by the 3-loop self-energy master integrals with four or five propagators with generic masses, including the derivatives with respect to each of the squared masses and the external momentum invariant. These…

High Energy Physics - Phenomenology · Physics 2023-03-29 Stephen P. Martin

With a key improvement, the auxiliary mass flow method is now able to compute Feynman integrals encountered in cutting-edge collider processes. We have successfully applied it to compute some integrals involved in two-loop electroweak…

High Energy Physics - Phenomenology · Physics 2022-03-16 Xiao Liu , Yan-Qing Ma

The quarkonic contributions to the three-loop heavy-quark form factors for vector, axial-vector, scalar and pseudoscalar currents are described by closed form difference equations for the expansion coefficients in the limit of small…

High Energy Physics - Phenomenology · Physics 2023-07-07 Johannes Blümlein , Abilio De Freitas , Peter Marquard , Narayan Rana , Carsten Schneider

The static potential constitutes a fundamental quantity of Quantum Chromodynamics. It has recently been evaluated to three-loop accuracy. In this contribution we provide details on the calculation and present results for the 14 master…

High Energy Physics - Phenomenology · Physics 2010-12-13 Alexander V. Smirnov , Vladimir A. Smirnov , Matthias Steinhauser

We present a systematic method for reducing an arbitrary one-loop N-point massless Feynman integral with generic 4-dimensional momenta to a set comprised of eight fundamental scalar integrals: six box integrals in D=6, a triangle integral…

High Energy Physics - Phenomenology · Physics 2009-11-10 G. Duplancic , B. Nizic

Two-loop corrections to scattering amplitudes are crucial theoretical input for collider physics. Recent years have seen tremendous advances in computing Feynman integrals, scattering amplitudes, and cross sections for five-particle…

High Energy Physics - Theory · Physics 2022-03-30 Johannes Henn , Tiziano Peraro , Yingxuan Xu , Yang Zhang

Recently, algorithms for calculation of 3-loop propagator diagrams in HQET and on-shell QCD with a heavy quark have been constructed and implemented. These algorithms (based on integration by parts recurrence relations) reduce an arbitrary…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. G. Grozin

One of the most severe bottlenecks to reach high-precision predictions in QFT is the calculation of multiloop multileg Feynman integrals. Several new strategies have been proposed in the last years, allowing impressive results with deep…

High Energy Physics - Theory · Physics 2023-09-27 German F. R. Sborlini

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

We explore inequality constraints as a new tool for numerically evaluating Feynman integrals. A convergent Feynman integral is non-negative if the integrand is non-negative in either loop momentum space or Feynman parameter space. Applying…

High Energy Physics - Phenomenology · Physics 2023-10-05 Mao Zeng

We calculate the four-loop massless QCD corrections with two closed quark lines to quark and gluon form factors. The results for the gluon form factor and the singlet part of the quark form factor are given for the first time. From our…

High Energy Physics - Phenomenology · Physics 2019-07-22 Andreas von Manteuffel , Robert M. Schabinger

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 planar two-loop six-point Feynman integrals entering scattering observables in massless gauge theories such as QCD. A central result of this paper is the formulation of the differential-equations method under the algebraic…

High Energy Physics - Phenomenology · Physics 2024-12-31 Samuel Abreu , Pier Francesco Monni , Ben Page , Johann Usovitsch

We discuss a progress in calculation of Feynman integrals which has been done with help of the differential equation method and demonstrate the results for a class of two-point two-loop diagrams.

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov

The three-loop four-point function of stress-tensor multiplets in N=4 super Yang-Mills theory contains two so far unknown, off-shell, conformal integrals, in addition to the known, ladder-type integrals. In this paper we evaluate the…

High Energy Physics - Theory · Physics 2015-06-15 James Drummond , Claude Duhr , Burkhard Eden , Paul Heslop , Jeffrey Pennington , Vladimir A. Smirnov

Employing a cutting-edge bootstrap method, we analytically compute the three-loop pentagonal Wilson loop with Lagrangian insertion in planar $\mathcal{N}=4$ super-Yang-Mills theory. This object is conjectured to coincide with the maximally…

High Energy Physics - Theory · Physics 2025-12-22 Dmitry Chicherin , Johannes Henn , Yongqun Xu , Shun-Qing Zhang , Yang Zhang

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