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We present a precise and efficient computation of the two-loop amplitudes entering the Higgs boson pair production process via gluon fusion. Our approach is based on the small-Higgs-mass expansion while keeping the full dependence on the…

High Energy Physics - Phenomenology · Physics 2021-09-29 Guoxing Wang , Yuxuan Wang , Xiaofeng Xu , Yongqi Xu , Li Lin Yang

The factorisation of QCD matrix elements in the limit of two external partons becoming collinear is described by process-independent splitting amplitudes, which can be expanded systematically in perturbation theory. Working in conventional…

High Energy Physics - Phenomenology · Physics 2015-06-23 Claude Duhr , Thomas Gehrmann , Matthieu Jaquier

The calculation of the next-to-leading order QCD corrections to the production of a neutral Higgs-boson pair is briefly summarized. The dominant production mechanism is gluon fusion via top-quark loops, so that the QCD corrections can be…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Dawson , S. Dittmaier , M. Spira

We derive the separate helicity amplitudes involving the partial wave analysis in the process of pseudo-scalar meson photon productions with $J^P=3/2^+$, which is independent on model. According to parity, the general amplitude in the case…

High Energy Physics - Phenomenology · Physics 2015-08-24 Leihua Liu , Liye Xiao

In the framework of the Hard Thermal Loop effective theory, we calculate the two-loop contributions to hard lepton pair production in a quark-gluon plasma. We show that the result is free of any infrared and collinear singularity. We also…

High Energy Physics - Phenomenology · Physics 2009-11-07 P. Aurenche , F. Gelis , H. Zaraket

We calculate the light cone wave functions for a virtual photon to split into quark-antiquark states, including for the first time quark masses at one loop accuracy. These wave functions can be used to calculate cross sections for several…

High Energy Physics - Phenomenology · Physics 2022-08-31 G. Beuf , T. Lappi , R. Paatelainen

We compute the two-loop QED helicity amplitudes for the scattering of a lepton pair with an off-shell and an on-shell photon, $0\to\ell\bar\ell\gamma\gamma^*$, using the approximation of massless leptons. We express all master integrals…

High Energy Physics - Phenomenology · Physics 2023-11-10 Simon Badger , Jakub Kryś , Ryan Moodie , Simone Zoia

We present recent advancements in the computation of three-loop four-particle helicity amplitudes in full-color massless QCD. In this contribution, we focus on the $gg \to \gamma\gamma$ process. We show how to obtain compact analytic…

High Energy Physics - Phenomenology · Physics 2024-10-04 Piotr Bargiela

We calculate the two-loop corrections to heavy-quark pair production in the gluon fusion channel which arise from diagrams involving a closed light-quark loop. The calculation is carried out by keeping the exact dependence on the…

High Energy Physics - Phenomenology · Physics 2015-06-17 R. Bonciani , A. Ferroglia , T. Gehrmann , A. von Manteuffel , C. Studerus

Inelastic QED processes, the cross sections of which do not drop with increasing energy, play an important role at high-energy colliders. Such reactions have the form of two-jet processes with the exchange of a virtual photon in the…

High Energy Physics - Phenomenology · Physics 2011-09-13 C. Carimalo , A. Schiller , V. G. Serbo

We review recent developments for the calculation of Born amplitudes in QCD. This includes the computation of gluon helicity amplitudes from MHV vertices and an approach based on scalar propagators and a set of three- and four-valent…

High Energy Physics - Theory · Physics 2015-06-26 Christian Schwinn , Stefan Weinzierl

We present a leading colour computation of the double virtual contributions to top-quark pair production in association with a jet at a hadron collider at next-to-next-to-leading order in QCD. The finite remainders of the two-loop…

High Energy Physics - Phenomenology · Physics 2026-05-15 Simon Badger , Matteo Becchetti , Colomba Brancaccio , Michał Czakon , Heribertus Bayu Hartanto , Rene Poncelet , Simone Zoia

We compute two-loop corrections to the associated production of a Higgs boson with a $Z$ boson and to off-shell $Z$ boson pair production in the gluon fusion channel, mediated by a heavy quark. We perform deep expansions in the high-energy…

High Energy Physics - Phenomenology · Physics 2025-09-10 Joshua Davies , Dominik Grau , Kay Schönwald , Matthias Steinhauser , Daniel Stremmer , Marco Vitti

We calculate the order \alpha_s finite temperature correction to dilepton production in quark-gluon plasma arising from the two-loop photon self-energy diagrams for high invariant mass M >> T.

High Energy Physics - Phenomenology · Physics 2009-10-31 J. I. Kapusta , S. M. H. Wong

We calculate the two-loop QCD corrections to the production of the neutral supersymmetric Higgs bosons via the gluon fusion mechanism at hadron colliders, including the contributions of squark loops. To a good approximation, these…

High Energy Physics - Phenomenology · Physics 2010-04-06 S. Dawson , A. Djouadi , M. Spira

We present an analytic expression for the six-point all-plus helicity amplitude in QCD at two-loops. We compute the rational terms in a compact analytic form organised by their singularity structure.

High Energy Physics - Theory · Physics 2016-08-10 David C. Dunbar , Warren B. Perkins

We review on the calculation of the heavy-quark photo-production vector form factors, with the full dependence on the mass of the heavy-quark. The Feynman diagrams are evaluated within the dimensional regularization scheme and expressed in…

High Energy Physics - Phenomenology · Physics 2015-06-25 R. Bonciani

The observation of double and triple scalar boson production at hadron colliders could provide key information on the Higgs self couplings and the potential. As for single Higgs production the largest rates for multiple Higgs production…

High Energy Physics - Phenomenology · Physics 2015-06-22 F. Maltoni , E. Vryonidou , M. Zaro

We compute helicity amplitudes for the one-loop QCD corrections to top-quark pair production analytically in terms of a set of uniformly transcendental master integrals. We provide corrections up to $O(\epsilon^2)$ in the dimensional…

High Energy Physics - Phenomenology · Physics 2022-06-29 Simon Badger , Matteo Becchetti , Ekta Chaubey , Robin Marzucca , Francesco Sarandrea

We present a method for the integrand-level reduction of two-loop helicity amplitudes in both $d=4-2\epsilon$ and $d=4$ dimensions. The amplitude is expressed in terms of a set of Feynman integrals and their coefficients that depend on the…

High Energy Physics - Phenomenology · Physics 2025-11-14 Giuseppe Bevilacqua , Dhimiter Canko , Costas Papadopoulos , Aris Spourdalakis