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The possibility of treating colour in one-loop amplitude calculations alike the other quantum numbers is briefly discussed for semi-numerical algorithms based on generalized unitarity and parametric integration techniques. Numerical results…

High Energy Physics - Phenomenology · Physics 2015-03-17 Jan Winter

We compute the two-loop helicity amplitudes for the production of three photons at hadron colliders in QCD at leading-color. Using the two-loop numerical unitarity method coupled with analytic reconstruction techniques, we obtain the…

High Energy Physics - Phenomenology · Physics 2021-01-20 S. Abreu , B. Page , E. Pascual , V. Sotnikov

We apply the solution to the recursion relation for the double-off-shell quark current to the problem of computing one loop amplitudes with an arbitrary number of gluons. We are able to compute amplitudes for photon-gluon scattering,…

High Energy Physics - Phenomenology · Physics 2009-10-22 Gregory Mahlon

I present results for the resummation of soft and collinear gluon contributions to QCD hard-scattering cross sections at two loops. This requires the calculation of UV and IR divergences through two loops and the construction of soft…

High Energy Physics - Phenomenology · Physics 2010-11-19 Nikolaos Kidonakis

In this talk we discuss the color decomposition of tree-level and one-loop QCD amplitudes with arbitrary numbers of quarks and gluons. We present a method for the decomposition of partial amplitudes into primitive amplitudes, which is based…

High Energy Physics - Phenomenology · Physics 2014-07-03 Christian Reuschle , Stefan Weinzierl

We consider the three-loop scattering amplitudes for the production of a pair of photons in quark-antiquark annihilation in Quantum Chromodynamics (QCD). We use suitably defined projectors to efficiently calculate all helicity amplitudes.…

High Energy Physics - Phenomenology · Physics 2021-03-24 Fabrizio Caola , Andreas von Manteuffel , Lorenzo Tancredi

We compute the full-color two-loop five-gluon amplitude for the all-plus helicity configuration. In order to achieve this, we calculate the required master integrals for all permutations of the external legs, in the physical scattering…

High Energy Physics - Phenomenology · Physics 2019-08-21 S. Badger , D. Chicherin , T. Gehrmann , G. Heinrich , J. M. Henn , T. Peraro , P. Wasser , Y. Zhang , S. Zoia

I review the recent progress in the evaluation of two-loop massive QCD amplitudes necessary for the description of hadronic scattering processes at the LHC. I put a special emphasis on the case of top-quark final states.

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Czakon

Scattering amplitudes with spinning particles are shown to decompose into multiple copies of simple building blocks to all loop orders, which can be used to efficiently reduce these amplitudes to sums over scalar integrals. Absence of…

High Energy Physics - Phenomenology · Physics 2018-05-28 Rutger H. Boels , Qingjun Jin , Hui Luo

Pushing the reach of NNLO QCD predictions to $2\to3$ production processes is one of the pillars of precision phenomenology program at the LHC. In this talk we will overview recent results and developments in the calculation of two-loop…

High Energy Physics - Phenomenology · Physics 2022-07-26 V. Sotnikov

The numerical unitarity approach has been important for obtaining reliable QCD predictions for the LHC. Here I discuss the extension of the approach beyond the leading quantum corrections for computing multi-loop amplitudes. The numerical…

High Energy Physics - Phenomenology · Physics 2017-03-27 Harald Ita

We present the leading-color two-loop QCD corrections for the scattering of four partons and a $W$ boson, including its leptonic decay. The amplitudes are assembled from the planar two-loop helicity amplitudes for four partons and a vector…

High Energy Physics - Phenomenology · Physics 2022-04-12 S. Abreu , F. Febres Cordero , H. Ita , M. Klinkert , B. Page , V. Sotnikov

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 report on the advances in the calculation of the two-loop scattering amplitudes for five-particle processes with one off-shell leg. Focusing on the production of a Higgs boson in association with a bottom quark pair, we outline how the…

High Energy Physics - Phenomenology · Physics 2023-03-01 Jakub Kryś

We present the O(alphas^4) virtual QCD corrections to the scattering process of massless quark qqbar -> gg due to the interference of tree and two-loop amplitudes and to the self-interference of one-loop amplitudes. We work in conventional…

High Energy Physics - Phenomenology · Physics 2008-11-26 C. Anastasiou , E. W. N. Glover , C. Oleari , M. E. Tejeda-Yeomans

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 virtual contributions up to two loop level in perturbative Quantum Chromodynamic (QCD) to the decay of pseudo-scalar Higgs boson ($A$) to three gluons ($g$) and also to quark ($q$), anti-quark ($\overline q$) and a gluon. With…

High Energy Physics - Phenomenology · Physics 2024-11-20 Pulak Banerjee , Prasanna K. Dhani , V. Ravindran

We present a semi-analytic method for the integrand reduction of one-loop amplitudes, based on the systematic application of the Laurent expansions to the integrand-decomposition. In the asymptotic limit, the coefficients of the master…

High Energy Physics - Phenomenology · Physics 2015-06-04 Pierpaolo Mastrolia , Edoardo Mirabella , Tiziano Peraro

We address the analytic computation of the two-loop scattering amplitudes for the production of two photons in parton-parton scattering, mediated by loops of heavy quarks. Due to the presence of integrals of elliptic type, both partonic…

High Energy Physics - Phenomenology · Physics 2025-02-04 Matteo Becchetti , Federico Coro , Christoph Nega , Lorenzo Tancredi , Fabian J. Wagner

We derive the two-loop QCD helicity amplitudes for the processes $l q \to l qg$ ($l \bar q \to l \bar q g$) and $l g \to l q\bar q$, which are the partonic reactions yielding $(2+1)$-jet final states in deep inelastic lepton nucleon…

High Energy Physics - Phenomenology · Physics 2009-06-25 T. Gehrmann , E. W. N. Glover