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Related papers: Two-loop QCD helicity amplitudes for massless quar…

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We present advances in the development of the numerical unitarity method for the computation of multi-loop amplitudes in QCD. As an application, we show results for all the leading-color two-loop five-gluon helicity amplitudes. The…

High Energy Physics - Phenomenology · Physics 2018-07-26 Samuel Abreu , Fernando Febres Cordero , Harald Ita , Ben Page , Mao Zeng

We present a new method for computing multi-loop scattering amplitudes in Quantum Field Theory. It extends the Generalized Unitarity method by constraining not only the integrand of the amplitude but also its full integrated form. Our…

High Energy Physics - Theory · Physics 2025-12-18 Piotr Bargiela

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

We study two-to-two parton scattering amplitudes in the high-energy limit of perturbative QCD by iteratively solving the BFKL equation. This allows us to predict the imaginary part of the amplitude to leading-logarithmic order for arbitrary…

High Energy Physics - Phenomenology · Physics 2020-06-03 Simon Caron-Huot , Einan Gardi , Joscha Reichel , Leonardo Vernazza

We present the two-loop QCD corrections to the amplitude of the Higgs production associated with a $Z$ boson via the bottom quark-antiquark annihilation channel with a non-vanishing bottom-quark Yukawa coupling. The computation is performed…

High Energy Physics - Phenomenology · Physics 2019-12-16 Taushif Ahmed , A. H. Ajjath , Long Chen , Prasanna K. Dhani , Pooja Mukherjee , V. Ravindran

In this paper, we present analytical results for the two-loop QCD corrections to the production of two partons or a photon and a parton in hadronic collisions, mediated by loops of massive quarks. These amplitudes involve Feynman integrals…

High Energy Physics - Phenomenology · Physics 2025-09-22 Federico Coro , Christoph Nega , Lorenzo Tancredi , Fabian J. Wagner

We perform a dedicated study of the $q \bar{q}$-initiated two-loop electroweak-QCD Drell-Yan scattering amplitude in dimensional regularization schemes for vanishing light quark and lepton masses. For the relative order $\alpha$ and…

High Energy Physics - Phenomenology · Physics 2023-01-11 Matthias Heller , Andreas von Manteuffel , Robert M. Schabinger , Hubert Spiesberger

We present a calculation of the bosonic contribution to the two-loop mixed QCD-electroweak scattering amplitudes for $Z$-boson production in association with one hard jet at hadron colliders. We employ a method to calculate amplitudes in…

High Energy Physics - Phenomenology · Physics 2024-09-30 Piotr Bargiela , Fabrizio Caola , Herschel Chawdhry , Xiao Liu

We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n-2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared-…

High Energy Physics - Phenomenology · Physics 2010-11-15 Zvi Bern , Lance J. Dixon , David A. Kosower

The spinor-helicity formalism has proven to be very efficient in the calculation of scattering amplitudes in quantum field theory, while the loop tree duality (LTD) representation of multi-loop integrals exhibits appealing and interesting…

High Energy Physics - Phenomenology · Physics 2021-01-27 Felix Driencourt-Mangin , German Rodrigo , German F. R. Sborlini , William J. Torres Bobadilla

Recent Developments in computing very specific helicity amplitudes in two loop QCD are presented. The techniques focus upon the singular structure of the amplitude rather than on a diagramatic and integration approach

High Energy Physics - Phenomenology · Physics 2017-12-15 David C. Dunbar , John H Godwin , Guy R. Jehu , Warren B. Perkins

The infrared exponentiation properties of dimensionally-regularized multi-loop scattering amplitudes are typically hidden at the level of the integrand, materializing only after integral evaluation. We address this long-standing problem by…

High Energy Physics - Theory · Physics 2019-07-22 Robert M. Schabinger

We review the current status of high-multiplicity double-virtual QCD corrections to processes relevant for LHC phenomenology. In particular, we discuss the recent full-color calculation of the five-parton process, whose two-loop amplitudes…

High Energy Physics - Phenomenology · Physics 2024-06-27 Giuseppe De Laurentis

We present a complete set of analytic helicity amplitudes for top quark pair production via gluon fusion at two-loops in QCD. For the first time, we include corrections due to massive fermion loops which give rise to integrals over elliptic…

High Energy Physics - Phenomenology · Physics 2021-07-14 Simon Badger , Ekta Chaubey , Heribertus Bayu Hartanto , Robin Marzucca

In this note, we propose a factorization formula for gauge-theory scattering amplitudes up to two loops in the high-energy boosted limit. Our formula extends existing results in the literature by incorporating the contributions from massive…

High Energy Physics - Phenomenology · Physics 2023-12-20 Guoxing Wang , Tianya Xia , Li Lin Yang , Xiaoping Ye

We compute the two-loop helicity amplitudes for the scattering of five gluons, including all contributions beyond the leading-color approximation. The analytic expressions are represented as linear combinations of transcendental functions…

High Energy Physics - Phenomenology · Physics 2024-05-15 Giuseppe De Laurentis , Harald Ita , Maximillian Klinkert , Vasily Sotnikov

We establish an efficient polynomial-complexity algorithm for one-loop calculations, based on generalized $D$-dimensional unitarity. It allows automated computations of both cut-constructible {\it and} rational parts of one-loop scattering…

High Energy Physics - Phenomenology · Physics 2009-09-17 Walter T. Giele , Zoltan Kunszt , Kirill Melnikov

We present novel techniques for the computation of three-loop four-parton scattering amplitudes in full color, non-planar gauge theories. We elaborate on how the analytic results for these amplitudes can be used to confirm the conjectured…

High Energy Physics - Phenomenology · Physics 2022-08-18 Amlan Chakraborty , Giulio Gambuti

We combine the unitarity method with the six-dimensional helicity formalism of Cheung and O'Connell to construct loop-level scattering amplitudes. As a first example, we construct dimensionally regularized QCD one-loop four-point…

High Energy Physics - Theory · Physics 2015-03-17 Zvi Bern , John Joseph Carrasco , Tristan Dennen , Yu-tin Huang , Harald Ita

We present the two-loop virtual QCD corrections to the production of heavy quarks in gluon fusion. The results are exact in the limit when all kinematical invariants are large compared to the mass of the heavy quark up to terms suppressed…

High Energy Physics - Phenomenology · Physics 2010-04-05 M. Czakon , A. Mitov , S. Moch