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

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A way to efficiently compute helicity amplitudes for arbitrary tree-level scattering processes in QCD is presented. The scattering amplitude is evaluated recursively through a set of Dyson-Schwinger equations. The computational cost of this…

High Energy Physics - Phenomenology · Physics 2009-11-11 Costas G. Papadopoulos , Malgorzata Worek

In this paper, we study a novel behavior developed by certain tree-level scalar scattering amplitudes, including the biadjoint, NLSM, and special Galileon, when a subset of kinematic invariants vanishes without producing a singularity. This…

High Energy Physics - Theory · Physics 2022-09-14 Freddy Cachazo , Nick Early , Bruno Umbert

In this paper we present a new derivation of the QCD factorization. We deduce the k_T- and collinear factorizations for the DIS structure functions by consecutive reductions of a more general theoretical construction. We begin by studying…

High Energy Physics - Phenomenology · Physics 2011-09-28 B. I. Ermolaev , M. Greco , S. I. Troyan

In this paper, we study the newly discovered universal splitting behavior for tree-level scattering amplitudes of particles and strings~\cite{Cao:2024gln}: when a set of Mandelstam variables (and Lorentz products involving polarizations for…

High Energy Physics - Theory · Physics 2025-01-15 Qu Cao , Jin Dong , Song He , Canxin Shi , Fanky Zhu

In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes.…

High Energy Physics - Phenomenology · Physics 2009-08-07 Darren Forde

We initiate the study of multiloop scattering amplitudes in the Nambu-Goto theory on the worldsheet of a non-critical string. We start with a brute force calculation of two loop four particle scattering. Somewhat surprisingly, even though…

High Energy Physics - Theory · Physics 2016-05-20 Peter Conkey , Sergei Dubovsky

We update our approximate parametrizations of the three-loop splitting functions for the evolution of unpolarized parton densities in perturbative QCD. The new information taken into account is given by the additional Mellin moments…

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

We have computed the complete next-to-next-to-leading order (NNLO) contributions to the splitting functions governing the evolution of unpolarized parton densities in perturbative QCD. Our results agree with all partial results available in…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. Moch , J. A. M. Vermaseren , A. Vogt

We complete the study of two-loop infrared singularities of scattering amplitudes with an arbitrary number of massive and massless partons in non-abelian gauge theories. To this end, we calculate the universal functions F_1 and f_2, which…

High Energy Physics - Phenomenology · Physics 2010-02-22 Andrea Ferroglia , Matthias Neubert , Ben D. Pecjak , Li Lin Yang

We introduce a formalism for describing four-dimensional scattering amplitudes for particles of any mass and spin. This naturally extends the familiar spinor-helicity formalism for massless particles to one where these variables carry an…

High Energy Physics - Theory · Physics 2021-11-02 Nima Arkani-Hamed , Tzu-Chen Huang , Yu-tin Huang

We review the recently developed bootstrap method for the computation of high-multiplicity QCD amplitudes at one loop. We illustrate the general algorithm step by step with a six-point example. The method combines (generalized) unitarity…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger

This is the first in a series of papers presenting a new understanding of scattering amplitudes based on fundamentally combinatorial ideas in the kinematic space of the scattering data. We study the simplest theory of colored scalar…

High Energy Physics - Theory · Physics 2024-10-01 N. Arkani-Hamed , H. Frost , G. Salvatori , P-G. Plamondon , H. Thomas

We introduce a new technique to generate scattering amplitudes at one loop. Traditional tree algorithms, which handle diagrams with fixed momenta, are promoted to generators of loop-momentum polynomials that we call open loops. Combining…

High Energy Physics - Phenomenology · Physics 2013-05-30 Fabio Cascioli , Philipp Maierhöfer , Stefano Pozzorini

We study the collinear factorization of off-shell scattering amplitudes in maximally supersymmetric Yang-Mills (sYM) theory. These are constructed starting from six-dimensional N = (1,1) sYM, taking advantage of an available unconstrained…

High Energy Physics - Theory · Physics 2025-03-24 A. V. Belitsky

We present the one-loop QCD amplitudes for two external massless quarks and three external gluons ($\bar{q}qggg$). This completes the set of one-loop amplitudes needed for the next-to-leading-order corrections to three-jet production at…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , L. Dixon , D. A. Kosower

Over the past couple of years we have had significant progress in determining long-distance singularities in gauge-theory scattering amplitudes of massless particles beyond the planar limit. Upon considering all kinematic invariants much…

High Energy Physics - Phenomenology · Physics 2018-01-11 Einan Gardi

We present an expression for the QCD amplitude for a general hard scattering process with any number of soft gluon emissions, to one-loop accuracy. The amplitude is written in two different but equivalent ways: as a product of operators…

High Energy Physics - Phenomenology · Physics 2016-06-01 René Ángeles-Martínez , Jeffrey R. Forshaw , Michael H. Seymour

We propose a new splitting behavior of tree-level string/particle amplitudes for scalars, gluons and gravitons. We identify certain subspaces in the space of Mandelstam variables, where the universal Koba-Nielsen factor splits into two…

High Energy Physics - Theory · Physics 2024-08-23 Qu Cao , Jin Dong , Song He , Canxin Shi

The calculation of scattering amplitudes at higher orders in perturbation theory has reached a high degree of maturity. However, their usage to produce physical predictions within Monte Carlo programs is often precluded by the slow…

High Energy Physics - Phenomenology · Physics 2025-09-24 Víctor Bresó , Gudrun Heinrich , Vitaly Magerya , Anton Olsson

We review recent developments in the calculation of QCD loop amplitudes with several external legs, and their application to next-to-leading order jet production cross-sections. When a number of calculational tools are combined together ---…

High Energy Physics - Phenomenology · Physics 2007-05-23 Z. Bern , L. Dixon , D. A. Kosower , A. Signer
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