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Related papers: One-loop results for three-gluon vertex in arbitra…

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There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in quantum chromodynamics, leading to the…

High Energy Physics - Phenomenology · Physics 2017-04-05 R. Bermudez , L. Albino , L. X. Gutiérrez-Guerrero , M. E. Tejeda-Yeomans , A. Bashir

An efficient numerical algorithm to evaluate one-loop amplitudes using tensor integrals is presented. In particular, it is shown by explicit calculations that for ordered QCD amplitudes with a number of external legs up to 10, its…

High Energy Physics - Phenomenology · Physics 2009-08-11 A. van Hameren

We compute the general expression of the one-loop vertex correction in an arbitrary plane-wave background field for the case of two on-shell external electrons and an off-shell external photon. The properties of the vertex corrections under…

High Energy Physics - Phenomenology · Physics 2020-11-04 A. Di Piazza , M. A. Lopez-Lopez

The gauge-invariant three-gluon vertex obtained from the pinch technique is characterized by thirteen nonzero form factors, which are given in complete generality for unbroken gauge theory at one loop. The results are given in $d$…

High Energy Physics - Phenomenology · Physics 2009-09-11 Michael Binger , Stanley J. Brodsky

We compute the contribution to the modulus of the one-loop effective action in pure non-Abelian Chern-Simons theory in an arbitrary covariant gauge. We find that the results are dependent on both the gauge parameter ($\alpha$) and the…

High Energy Physics - Theory · Physics 2009-10-30 F. A. Dilkes , L. C. Martin , D. G. C. McKeon , T. N. Sherry

We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons to three-loop order within massless perturbative Quantum Chromodynamics. These results provide building blocks for…

High Energy Physics - Phenomenology · Physics 2009-06-30 P. A. Baikov , K. G. Chetyrkin , A. V. Smirnov , V. A. Smirnov , M. Steinhauser

We calculate the two-mass contribution to the 3-loop vacuum polarization of the gluon in Quantum Chromodynamics at virtuality $p^2 = 0$ for general masses and also present the analogous result for the photon in Quantum Electrodynamics.

High Energy Physics - Phenomenology · Physics 2017-10-13 J. Blümlein , A. De Freitas , C. Schneider , K. Schönwald

We present results for the six-gluon scattering amplitude at one-loop. Since our method is semi-numerical, it yields the result for arbitrary momenta and helicities of the external gluons. We evaluate the colour-ordered sub-amplitudes with…

High Energy Physics - Phenomenology · Physics 2009-11-11 R. K. Ellis , W. T. Giele , Giulia Zanderighi

We present an analytic method to compute the one-loop magnetic correction to the gluon polarization tensor starting from the Landau-level representation of the quark propagator in the presence of an external magnetic field. We show that the…

High Energy Physics - Theory · Physics 2020-02-26 Alejandro Ayala , Jorge David Castaño-Yepes , M. Loewe , Enrique Muñoz

We establish the general off-shell structure of the three neutral gauge boson self-couplings V1*V2*V3*, with applications to the Z*Z*Z*, Z*Z*gamma*, gamma*gamma*Z* cases. New coupling forms appear which do not exist when two gauge bosons…

High Energy Physics - Phenomenology · Physics 2011-03-23 G. J. Gounaris , J. Layssac , F. M. Renard

We apply differential equations technique to the calculation of the one-loop massless diagram with one offshell legs. Using reduction to $\epsilon$-form, we managed to obtain a simple one-fold integral representation exact in space-time…

High Energy Physics - Phenomenology · Physics 2017-02-15 Mikhail G. Kozlov

We consider one-loop five-point QCD amplitudes in next-to-multi-Regge kinematics, and evaluate the one-loop impact factor for the emission of two gluons. This is the last ingredient which is necessary to evaluate the gluon-jet impact factor…

High Energy Physics - Phenomenology · Physics 2021-06-30 Marc Canay , Vittorio Del Duca

We present the technical tools needed to compute any one-loop amplitude involving external spacetime fermions in a four-dimensional heterotic string model a` la Kawai-Lewellen-Tye. As an example, we compute the one-loop three-point…

High Energy Physics - Theory · Physics 2009-10-28 A. Pasquinucci , K. Roland

We describe techniques that simplify the calculation of one-loop QCD amplitudes with many external legs, which are needed for next-to-leading-order (NLO) corrections to multi-jet processes. The constraints imposed by perturbative unitarity,…

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

We develop an algorithm of polynomial complexity for evaluating one-loop amplitudes with an arbitrary number of external particles. The algorithm is implemented in the Rocket program. Starting from particle vertices given by Feynman rules,…

High Energy Physics - Phenomenology · Physics 2009-05-05 W. T. Giele , G. Zanderighi

We use on-shell recursion relations to compute analytically the one-loop corrections to maximally-helicity-violating n-gluon amplitudes in QCD. The cut-containing parts have been computed previously; our work supplies the remaining rational…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger , Zvi Bern , Lance J. Dixon , Darren Forde , David A. Kosower

We study the photon-quark-quark and Higgs-gluon-gluon form factors for on-shell massless quarks and gluons in perturbative QCD. Previous third-order results for the quark case are extended by calculating the fermion-loop contributions up to…

High Energy Physics - Phenomenology · Physics 2010-04-05 S. Moch , J. A. M. Vermaseren , A. Vogt

We present an analytic calculation of electron and tau O(alpha^3) loop effects on the muon anomalous magnetic moment. Computation of such three-loop diagrams with three mass scales is possible using asymptotic and eikonal expansions. An…

High Energy Physics - Phenomenology · Physics 2009-10-31 Andrzej Czarnecki , Maciej Skrzypek

Three-loop vacuum integrals are an important building block for the calculation of a wide range of three-loop corrections. Until now, only results for integrals with one and two independent mass scales are known, but in the electroweak…

High Energy Physics - Phenomenology · Physics 2021-04-08 Ayres Freitas

Evaluation of three- and four-point diagrams with massless internal particles and arbitrary external momenta is considered. Exact results for some two-loop diagrams (planar and non-planar three-point contributions and the "double box"…

High Energy Physics - Phenomenology · Physics 2007-05-23 N. I. Ussyukina , A. I. Davydychev