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Related papers: Massive non-planar two-loop four-point integrals w…

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Recent progress in the calculation of multi-loop, multi-scale diagrams is reviewed. Expansion techniques combined with new developments in Computer algebra allow to evaluate the R ratio for massive quarks up to order $\alpha_s^2$ and,…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. H. Kuehn

We investigate the high-energy production of tetraquark-jet systems at the LHC and its forthcoming High-Luminosity upgrade. In this review, we examine the leading-power fragmentation of fully heavy tetraquarks ($T_{4Q}$) in hadronic…

High Energy Physics - Phenomenology · Physics 2026-04-03 Francesco Giovanni Celiberto

We calculate the complete set of two-loop Master Integrals with two off mass-shell legs with massless internal propagators, that contribute to amplitudes of diboson $V_1V_2$ production at the LHC. This is done with the Simplified…

High Energy Physics - Phenomenology · Physics 2015-07-22 Costas G. Papadopoulos , Damiano Tommasini , Christopher Wever

In this paper we present the master integrals necessary for the analytic calculation of the box diagrams with one electron loop (N_{F}=1) entering in the 2-loop (\alpha^3) QED virtual corrections to the Bhabha scattering amplitude of the…

High Energy Physics - Phenomenology · Physics 2009-11-10 R. Bonciani , A. Ferroglia , P. Mastrolia , E. Remiddi , J. J. van der Bij

The calculation of the two-loop corrections to the three jet production rate and to event shapes in electron-positron annihilation requires the computation of a number of up to now unknown two-loop four-point master integrals with one…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. Gehrmann , E. Remiddi

In this work, we calculate two-loop six-point planar massless Feynman integrals at higher orders in the dimensional regulator $\epsilon$, corresponding to higher transcendental weights. In previous works, these integrals were calculated up…

High Energy Physics - Phenomenology · Physics 2026-04-03 Yuanche Liu , Antonela Matijašić , Tiziano Peraro , Yingxuan Xu , Zihua Yang , Yang Zhang

We report on the three Mathematica packages hexagon, CSectors, AMBRE. They are useful for the evaluation of one- and two-loop Feynman integrals with a dependence on several kinematical scales. These integrals are typically needed for LHC…

High Energy Physics - Phenomenology · Physics 2014-11-18 Janusz Gluza , Krzysztof Kajda , Tord Riemann , Valery Yundin

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 study the next-to-next-to-leading order (NNLO) evolution of flavour non-singlet quark densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. L. van Neerven , A. Vogt

We describe a first attempt to calculate scalar 2-loop box-functions with arbitrary internal masses, applying a novel method proposed in hep-ph/9407234. Four of the eight integrals are accessible to integration by means of the residue…

High Energy Physics - Phenomenology · Physics 2011-09-13 R. Kreckel , D. Kreimer , K. Schilcher

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 report on the progress in constructing contracted one-loop tensors. Analytic results for rank R=4 tensors, cross-checked numerically, are presented for the first time.

High Energy Physics - Phenomenology · Physics 2013-11-12 Andrea A. Almasy , Ievgen Dubovyk , J. Gluza , T. Riemann

We compute the two-loop corrections to the helicity amplitudes for the coupling of a massive vector boson to a massless quark-antiquark pair and a gluon, accounting for vector and axial-vector couplings of the vector boson and…

High Energy Physics - Phenomenology · Physics 2023-06-19 Thomas Gehrmann , Tiziano Peraro , Lorenzo Tancredi

We study the problem of calculating two-loop three-point diagrams with irreducible numerators (i.e. numerators which cannot be expressed in terms of the denominators). For the case of massless internal particles and arbitrary (off-shell)…

High Energy Physics - Phenomenology · Physics 2014-11-17 Natalia I. Ussyukina , Andrei I. Davydychev

We discuss various aspects of inclusive top-quark pair production based on TOPIXS, a new, flexible program that computes the production cross section at the Tevatron and LHC at next-to-next-to-leading logarithmic accuracy in soft and…

High Energy Physics - Phenomenology · Physics 2012-08-09 M. Beneke , P. Falgari , S. Klein , J. Piclum , C. Schwinn , M. Ubiali , F. Yan

Two-loop multi-leg form factors in off-shell kinematics require knowledge of planar and nonplanar double box Feynman diagrams with massless internal propagators. These are complicated functions of Mandelstam variables and external particle…

High Energy Physics - Theory · Physics 2024-02-29 A. V. Belitsky , V. A. Smirnov

We present and discuss the release of novel sets of collinear, variable-flavor-number-scheme fragmentation functions for axial-vector, fully heavy $T_{4c}(1^{+-})$ and $T_{4b}(1^{+-})$ tetraquarks. Working within the single-parton…

High Energy Physics - Phenomenology · Physics 2025-06-04 Francesco Giovanni Celiberto

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

We describe a method to numerically compute multi-loop integrals, depending on one dimensionless parameter $x$ and the dimension $d$, in the whole kinematic range of $x$. The method is based on differential equations, which, however, do not…

High Energy Physics - Phenomenology · Physics 2021-10-13 Matteo Fael , Fabian Lange , Kay Schönwald , Matthias Steinhauser

In this review, we present a new method for computing physical cross sections at NLO accuracy in QCD without using the standard Dimensional Regularisation. The algorithm is based on the Loop-Tree Duality theorem, which allow us to obtain…

High Energy Physics - Phenomenology · Physics 2016-11-23 R. J. Hernández-Pinto , F. Driencourt-Mangin , G. Rodrigo , G. F. R. Sborlini