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We present a prescription to calculate manifestly gauge invariant tree-level helicity amplitudes for arbitrary scattering processes with off-shell initial-state gluons within the kinematics of high-energy scattering. We show that it is…

High Energy Physics - Phenomenology · Physics 2013-09-24 A. van Hameren , P. Kotko , K. Kutak

Compact results are obtained for tree-level non-MHV amplitudes of six fermions and of four fermions and two gluons, by using extended BCF/BCFW rules. Combining with previous results, complete set of tree amplitudes of six partons are now…

High Energy Physics - Theory · Physics 2009-11-11 Mingxing Luo , Congkao Wen

We compute amplitudes for the process $g^* g^* \to q \overline q V^*$ (two virtual gluons into a quark, antiquark and a boson) at the tree level using the spinor-helicity formalism. The resulting analytic expressions are much shorter than…

High Energy Physics - Phenomenology · Physics 2024-10-11 Jan Ferdyan , Błażej Ruba

In unitarity cut method, compact input of on-shell tree level amplitudes is crucial to simplify calculations. Although BCFW on-shell recursion relation gives very compact tree level amplitudes, they usually contain spurious poles. In this…

High Energy Physics - Phenomenology · Physics 2009-02-02 Bo Feng , Gang Yang

We present the publicly available program NGluon allowing the numerical evaluation of primitive amplitudes at one-loop order in massless QCD. The program allows the computation of one-loop amplitudes for an arbitrary number of gluons. The…

High Energy Physics - Phenomenology · Physics 2012-08-02 Simon Badger , Benedikt Biedermann , Peter Uwer

This thesis aims at providing better understanding of the perturbative expansion of gauge theories with and without supersymmetry. At tree level, the BCFW recursion relations are analyzed with respect to their validity for general off-shell…

High Energy Physics - Theory · Physics 2014-09-30 Alexander Ochirov

We study the QCD scattering amplitudes for \bar{q}q \to gg and \bar{q}q \to ggg where q is a massive fermion. Using a particular choice of massive fermion spinor we are able to derive very compact expressions for the partial spin amplitudes…

High Energy Physics - Phenomenology · Physics 2009-01-07 K. J. Ozeren , W. J. Stirling

We derive general tree-level recursion relations for amplitudes which include massive propagating particles. As an illustration, we apply these recursion relations to scattering amplitudes of gluons coupled to massive scalars. We provide…

High Energy Physics - Theory · Physics 2009-11-11 S. D. Badger , E. W. N. Glover , V. V. Khoze , P. Svrcek

Using the recently introduced recursion relations with covariant massive-massless shift, we study tree-level scattering amplitudes involving a pair of massive vector bosons and an arbitrary number of gluons in the massive spinor-helicity…

High Energy Physics - Theory · Physics 2022-08-24 Sourav Ballav , Arkajyoti Manna

We show how to apply the BCFW recursion relation to Feynman loop integrals with the help of the Feynman-tree theorem. We deconstruct in this way all Feynman diagrams in terms of on-shell subamplitudes. Every cut originating from the…

High Energy Physics - Theory · Physics 2016-05-18 M. Maniatis , C. M. Reyes

The recursive method of Berends and Giele to compute tree-level gluon amplitudes is revisited using the framework of ten-dimensional super Yang-Mills. First we prove that the pure spinor formula to compute SYM tree amplitudes derived in…

High Energy Physics - Theory · Physics 2016-04-12 Carlos R. Mafra , Oliver Schlotterer

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

The BCFW recursion relation allows to find out the tree-level scattering amplitudes for gluons and tensor gauge bosons in generalized Yang-Mills theory. We demonstrate that the corresponding MHV amplitudes for the tensor gauge bosons of…

High Energy Physics - Theory · Physics 2012-06-07 Ignatios Antoniadis , George Savvidy

We present on the use of on-shell recursion relations. These can be used not only for calculating tree amplitudes, including those with masses, but also to compute analytically the missing rational terms of one-loop QCD amplitudes. Combined…

High Energy Physics - Phenomenology · Physics 2017-08-23 Darren Forde

We investigate the application of the BCFW recursion relation to scattering amplitudes with one off-shell particle in a Yang-Mills theory with fermions. We provide a set of conditions of applicability of the BCFW recursion, stressing some…

High Energy Physics - Phenomenology · Physics 2016-11-15 A. van Hameren , M. Serino

Recently, spin-one wavefunctions in four dimensions that are conformal primaries of the Lorentz group SL(2,C) were constructed. We compute low-point, tree-level gluon scattering amplitudes in the space of these conformal primary…

High Energy Physics - Theory · Physics 2017-11-01 Sabrina Pasterski , Shu-Heng Shao , Andrew Strominger

We propose a quantum algorithm for computing the n-gluon maximally helicity violating (MHV) tree-level scattering amplitude. We revisit a newly proposed method for unitarisation of non-unitary operations and present how this implementation…

High Energy Physics - Phenomenology · Physics 2026-04-17 Erik Bashore , Stefano Moretti , Timea Vitos

We use on-shell methods to calculate tree-level effective field theory (EFT) amplitudes, with no reference to the EFT operators. Lorentz symmetry, unitarity and Bose statistics determine the allowed kinematical structures. As a by-product,…

High Energy Physics - Phenomenology · Physics 2019-03-27 Yael Shadmi , Yaniv Weiss

The computation of two-loop amplitudes for the production of multiple Higgs and electroweak gauge bosons via gluon fusion with exact dependence on quark masses relies primarily on numerical methods. We propose a framework that enables their…

High Energy Physics - Phenomenology · Physics 2024-11-13 Charalampos Anastasiou , Julia Karlen , George Sterman , Aniruddha Venkata

The compute efficiency of Monte-Carlo event generators for the Large Hadron Collider is expected to become a major bottleneck for simulations in the high-luminosity phase. Aiming at the development of a full-fledged generator for modern…

High Energy Physics - Phenomenology · Physics 2022-01-11 Enrico Bothmann , Walter Giele , Stefan Hoeche , Joshua Isaacson , Max Knobbe