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Related papers: Two-loop amplitudes for e+ e- -> q qbar g: the nf-…

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We present the calculation of the nf-contributions to the two-loop amplitude for e+ e- --> q qbar g and give results for the full one-loop amplitude to order eps^2 in the dimensional regularization parameter. Our results agree with those…

High Energy Physics - Phenomenology · Physics 2009-09-29 Sven Moch , Peter Uwer , Stefan Weinzierl

We review a new technique for the calculation of two-loop amplitudes and discuss as an example the fermionic contributions to e+ e- --> q qbar g.

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Moch , P. Uwer , S. Weinzierl

We present the calculation of the fermionic contribution to the QCD two-loop amplitude for e^+e^- --> q qbar g.

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Moch , P. Uwer , S. Weinzierl

We compute the two-loop QCD helicity amplitudes for the process e^+e^- --> q bar{q} g. The amplitudes are extracted in a scheme-independent manner from the coefficients appearing in the general tensorial structure for this process. The…

High Energy Physics - Phenomenology · Physics 2010-04-06 L. W. Garland , T. Gehrmann , E. W. N. Glover , A. Koukoutsakis , E. Remiddi

We report on the two-loop amplitude computation for the mixed QCD-electroweak corrections to the process $gg \to Hg$, with exact dependence on the electroweak boson masses. This amplitude has been employed in the computation of…

High Energy Physics - Phenomenology · Physics 2022-05-11 Matteo Becchetti , Francesco Moriello , Armin Schweitzer

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

I have evaluated up to 1100 digits of precision the contribution of the 891 4-loop Feynman diagrams contributing to the electron $g$-$2$ in QED. The total mass-independent 4-loop contribution is $ a_e =…

High Energy Physics - Phenomenology · Physics 2017-08-23 Stefano Laporta

We calculate the two-loop QCD corrections to $gg \to ZZ$ involving a closed top-quark loop. We present a new method to systematically construct linear combinations of Feynman integrals with a convergent parametric representation, where we…

High Energy Physics - Phenomenology · Physics 2021-06-16 Bakul Agarwal , Stephen P. Jones , Andreas von Manteuffel

We present an algorithm for the numerical calculation of one-loop QCD amplitudes. The algorithm consists of subtraction terms, approximating the soft, collinear and ultraviolet divergences of one-loop amplitudes and a method to deform the…

High Energy Physics - Phenomenology · Physics 2010-12-09 Sebastian Becker , Christian Reuschle , Stefan Weinzierl

In this talk we discuss an algorithm for the numerical calculation of one-loop QCD amplitudes and present results at next-to-leading order for jet observables in electron-positron annihilation calculated with the above-mentioned method. The…

High Energy Physics - Phenomenology · Physics 2011-12-16 S. Becker , D. Goetz , C. Reuschle , C. Schwan , S. Weinzierl

We present the first full analytic evaluation of the scattering amplitude for the process $q {\bar q} \to Q {\bar Q}$ up-to two loops in Quantum Chromodynamics, for a massless $(q)$ and a massive $(Q)$ quark flavour. The interference terms…

High Energy Physics - Phenomenology · Physics 2022-09-28 Manoj K. Mandal , Pierpaolo Mastrolia , Jonathan Ronca , William J. Torres Bobadilla

We compute the two-loop QCD corrections to amplitudes for processes $g g \to H g, q g \to H q$ and $q \bar{q} \to H g$ in the limit when the Higgs transverse momentum is larger than the top quark mass, $p_\perp \gg m_t$. These amplitudes…

High Energy Physics - Phenomenology · Physics 2018-04-04 Kirill Kudashkin , Kirill Melnikov , Christopher Wever

We calculate the contributions to the two-loop scattering amplitudes $h \to gg$, $h \to ggg$ and $h \to q \bar q g$ that arise from a modified trilinear Higgs coupling $\lambda$. Analytic expressions are obtained by performing an asymptotic…

High Energy Physics - Phenomenology · Physics 2019-05-01 Martin Gorbahn , Ulrich Haisch

We compute the two-loop QCD corrections to $q g \to H q$ and $q \bar{q} \to H g$ amplitudes mediated by loops of nearly massless quarks. These amplitudes provide the last missing ingredient required to compute the NLO QCD corrections to the…

High Energy Physics - Phenomenology · Physics 2017-03-22 Kirill Melnikov , Lorenzo Tancredi , Christopher Wever

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 present the two-loop pure gauge contribution to the gluon-gluon scattering amplitude with maximal helicity violation. Our construction of the amplitude does not rely directly on Feynman diagrams, but instead uses its analytic properties…

High Energy Physics - Phenomenology · Physics 2011-06-27 Z. Bern , L. Dixon , D. A. Kosower

We compute the two-loop mixed QCD-Electroweak corrections to $q \overline{q} \to H g$ and its crossed channels $q g \to H q$, $\overline{q} g \to H \overline{q}$, limiting ourselves to the contribution of light virtual quarks. We compute…

High Energy Physics - Phenomenology · Physics 2022-07-18 Marco Bonetti , Erik Panzer , Lorenzo Tancredi

I discuss the status of the computation of the two-loop QCD corrections to top-quark pair production associated with a jet at hadron colliders. This amplitude is a missing ingredient for next-to-next-to-leading order (NNLO) QCD predictions.…

High Energy Physics - Phenomenology · Physics 2024-11-19 Colomba Brancaccio

We present the first numerical computation of two-loop amplitudes based on the unitarity method. As a proof of principle, we compute the four-gluon process. We discuss the new method, analyze its numerical properties and apply it to…

High Energy Physics - Phenomenology · Physics 2017-10-11 S. Abreu , F. Febres Cordero , H. Ita , M. Jaquier , B. Page , M. Zeng

We compute the one-loop QCD amplitude for the process gg-->Q\bar{Q} in dimensional regularization through order \epsilon^2 in the dimensional regulator and for arbitrary quark mass values. This result is an ingredient of the NNLO…

High Energy Physics - Phenomenology · Physics 2008-12-30 Charalampos Anastasiou , S. Mert Aybat
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