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Related papers: Splitting amplitudes at N$^3$LO in QCD

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We present the analytic form of all leading-color two-loop five-parton helicity amplitudes in QCD. The results are analytically reconstructed from exact numerical evaluations over finite fields. Combining a judicious choice of variables…

High Energy Physics - Phenomenology · Physics 2019-05-23 S. Abreu , J. Dormans , F. Febres Cordero , H. Ita , B. Page , V. Sotnikov

The infrared divergences of QCD scattering amplitudes can be derived from an anomalous dimension \Gamma, which is a matrix in color space and depends on the momenta and masses of the external partons. It has recently been shown that in…

High Energy Physics - Phenomenology · Physics 2009-11-19 Andrea Ferroglia , Matthias Neubert , Ben D. Pecjak , Li Lin Yang

We propose a first implementation of the integrand-reduction method for two-loop scattering amplitudes. We show that the residues of the amplitudes on multi-particle cuts are polynomials in the irreducible scalar products involving the loop…

High Energy Physics - Phenomenology · Physics 2015-05-30 Pierpaolo Mastrolia , Giovanni Ossola

We present the next-to-next-to-leading order (NNLO) contributions to the main splitting functions for the evolution of longitudinally polarized parton densities of hadrons in perturbative QCD. The quark-quark and gluon-quark splitting…

High Energy Physics - Phenomenology · Physics 2015-06-22 S. Moch , J. A. M. Vermaseren , A. Vogt

We calculate the one-loop QCD virtual corrections to all helicity amplitudes for parton level virtual Compton scattering processes. We include the amplitudes both on quark target process $\gamma^* q\to\gamma q$ and on gluon target process…

High Energy Physics - Phenomenology · Physics 2009-11-10 H. W. Huang , T. Morii

When the available collision energy is much above the mass of the particles involved, scattering amplitudes feature kinematic configurations that are enhanced by the much lower virtuality of some intermediate particle. Such configurations…

High Energy Physics - Phenomenology · Physics 2024-05-15 Filippo Nardi , Lorenzo Ricci , Andrea Wulzer

We present results for the six-gluon scattering amplitude at one-loop. Since our method is semi-numerical, it yields the result for arbitrary momenta and helicities of the external gluons. We evaluate the colour-ordered sub-amplitudes with…

High Energy Physics - Phenomenology · Physics 2009-11-11 R. K. Ellis , W. T. Giele , Giulia Zanderighi

We present the next-to-next-to-next-to-leading order (N^3LO) contributions to the non-singlet splitting functions for both parton distribution and fragmentation functions in perturbative QCD. The exact expressions are derived for the terms…

High Energy Physics - Phenomenology · Physics 2017-10-25 S. Moch , B. Ruijl , T. Ueda , J. A. M. Vermaseren , A. Vogt

We suggest a new approach for the automatic and fully numerical evaluation of one-loop scattering amplitudes in perturbative quantum field theory. We use suitably formulated dispersion relations to perform the calculation as a convolution…

High Energy Physics - Phenomenology · Physics 2008-09-29 M. Moretti , F. Piccinini , A. D. Polosa

The soft anomalous dimension governs the infrared singularities of scattering amplitudes to all orders in perturbative quantum field theory, and is a crucial ingredient in both formal and phenomenological applications of non-abelian gauge…

High Energy Physics - Phenomenology · Physics 2017-10-25 Øyvind Almelid , Claude Duhr , Einan Gardi , Andrew McLeod , Chris D. White

We study the angular distributions of the splitting functions for processes for which a parton splits into three partons. Unlike the case of coherent branching, we find that both in vacuum and in the presence of the dense QCD matter, such…

High Energy Physics - Phenomenology · Physics 2015-06-16 Grigory Ovanesyan

We present the even-N moments N =< 20 of the fourth-order (N^3LO) contribution P_{gq}^(3)(x) to the quark-to-gluon splitting function in perturbative QCD. These moments, obtained by analytically computing off-shell operator matrix elements…

High Energy Physics - Phenomenology · Physics 2024-04-16 G. Falcioni , F. Herzog , S. Moch , A. Pelloni , A. Vogt

We investigate $2 \to 3$ QCD scattering amplitudes in multi-Regge kinematics, i.e. where the final partons are strongly ordered in rapidity. In this regime amplitudes exhibit intriguing factorisation properties which can be understood in…

High Energy Physics - Phenomenology · Physics 2025-04-11 Federico Buccioni , Fabrizio Caola , Federica Devoto , Giulio Gambuti

We present a systematic framework for the maximally-transcendental part of planar QCD scattering amplitudes and perform the first bootstrap computation of six-gluon MHV amplitudes in massless QCD at the symbol level. By analyzing the…

High Energy Physics - Theory · Physics 2026-02-04 Sérgio Carrôlo , Dmitry Chicherin , Johannes Henn , Qinglin Yang , Yang Zhang

We present the analytic form of the two-loop five-gluon scattering amplitudes in QCD for a complete set of independent helicity configurations of external gluons. These include the first analytic results for five-point two-loop amplitudes…

High Energy Physics - Phenomenology · Physics 2019-03-06 S. Abreu , J. Dormans , F. Febres Cordero , H. Ita , B. Page

We present a systematic decomposition of QCD splitting functions into scalar dipole radiators and pure splitting remainders up to second order in the strong coupling. The individual components contain terms that are formally sub-leading in…

High Energy Physics - Phenomenology · Physics 2026-02-06 John M. Campbell , Stefan Höche , Max Knobbe , Christian T. Preuss , Daniel Reichelt

We present a new and fully general algorithm for the automated construction of the integrands of two-loop scattering amplitudes. This is achieved through a generalisation of the open-loops method to two loops. The core of the algorithm…

High Energy Physics - Phenomenology · Physics 2022-07-18 Stefano Pozzorini , Natalie Schär , Max F. Zoller

We compute four-point scattering amplitudes in $\mathcal{N}=2$ SCQCD with general external matter configurations using $\mathcal{N}=1$ superspace Feynman diagrams, at one loop in the general case and up to two loops in the fundamental…

High Energy Physics - Theory · Physics 2015-01-22 Marta Leoni , Andrea Mauri , Alberto Santambrogio

We recently presented a new method for the evaluation of one-loop amplitude of arbitrary scattering processes, in which the reduction to scalar integrals is performed at the integrand level. In this talk, we review the main features of the…

High Energy Physics - Phenomenology · Physics 2007-09-17 Giovanni Ossola

We use lattice QCD calculations of the finite-volume spectra of systems of two and three mesons to determine, for the first time, three-particle scattering amplitudes with physical quark masses. Our results are for combinations of $\pi^+$…