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It is analysed the triple-cut of one-loop amplitudes in dimensional regularisation within spinor-helicity representation. The triple-cut is defined as a difference of two double-cuts with the same particle content, and a same propagator…

High Energy Physics - Theory · Physics 2008-11-26 Pierpaolo Mastrolia

We present compact analytic formulae for the one-loop amplitudes for Higgs + 4 parton scattering, $0 \to g g g g h$, $0 \to \bar{q} q gg h$ and $0\to \bar{q} q \bar{q}^\prime q^\prime h$, mediated by a loop of massive coloured quarks. We…

High Energy Physics - Phenomenology · Physics 2022-06-24 Lucy Budge , John M. Campbell , Giuseppe De Laurentis , R. Keith Ellis , Satyajit Seth

We present an overview of recent developments, based on on-shell techniques, in the calculation of multi-parton scattering amplitudes at one loop that are relevant for phenomenological studies at hadron colliders. These new on-shell methods…

High Energy Physics - Phenomenology · Physics 2015-05-14 Carola F. Berger , Darren Forde

We review the recent progress on the numerical implementation of the Loop-Tree Duality Method (LTDM) for the calculation of scattering amplitudes. A central point is the analysis of the singularities of the integrand. In the framework of…

High Energy Physics - Phenomenology · Physics 2015-09-25 Sebastian Buchta , Grigorios Chachamis , Petros Draggiotis , Ioannis Malamos , German Rodrigo

We present the public C++ library Ninja, which implements the Integrand Reduction via Laurent Expansion method for the computation of one-loop integrals. The algorithm is suited for applications to complex one-loop processes.

High Energy Physics - Phenomenology · Physics 2014-07-22 Tiziano Peraro

We present the first explicit formulae for the complete set of one-loop helicity amplitudes necessary for computing next-to-leading order corrections for e^+ e^- annihilation into four jets, for W, Z or Drell-Yan production in association…

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

Helicity amplitudes are the fundamental ingredients of many QCD calculations for multi-leg processes. We describe how these can seamlessly be combined with resummation in Soft-Collinear Effective Theory (SCET), by constructing a helicity…

High Energy Physics - Phenomenology · Physics 2016-05-23 Ian Moult , Iain W. Stewart , Frank J. Tackmann , Wouter J. Waalewijn

I describe a method for determining the coefficients of scalar integrals for one-loop amplitudes in quantum field theory. The method is based upon generalized unitarity and the behavior of amplitudes when the free parameters of the cut…

High Energy Physics - Phenomenology · Physics 2008-05-12 William B. Kilgore

We present a new Monte Carlo tool that computes full tree-level matrix elements in high-energy physics. The program accepts user-defined models and has no restrictions on the process multiplicity. To achieve acceptable performance, CAMORRA…

High Energy Physics - Phenomenology · Physics 2010-11-23 Ronald Kleiss , Gijs van den Oord

Using a heavy-mass effective field theory (HEFT), we study gravitational-wave emission in the scattering of two spinless black holes or neutron stars of arbitrary masses at next-to-leading order in the Post-Minkowskian expansion. We compute…

High Energy Physics - Theory · Physics 2024-11-08 Andreas Brandhuber , Graham R. Brown , Gang Chen , Stefano De Angelis , Joshua Gowdy , Gabriele Travaglini

Loop acceleration can be used to prove safety, reachability, runtime bounds, and (non-)termination of programs operating on integers. To this end, a variety of acceleration techniques has been proposed. However, all of them are monolithic:…

Logic in Computer Science · Computer Science 2020-02-21 Florian Frohn

We show some new applications of on-shell methods to calculate compact helicity amplitudes for t tbar production through gluon fusion. The rational and mass renormalisation contributions are extracted from two independent Feynman diagram…

High Energy Physics - Phenomenology · Physics 2011-02-11 Simon Badger , Ralf Sattler , Valery Yundin

The quantum amplitude for processes involving the formation and evaporation of black holes was previously calculated by means of a complex-time approach. In that treatment, we followed Feynman's $+i\epsilon$ approach in quantum field…

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. N. St. J. Farley , P. D. D'Eath

We develop a manifestly supersymmetric version of the generalized unitarity cut method for calculating scattering amplitudes in N=4 SYM theory. We illustrate the power of this method by computing the one-loop n-point NMHV super-amplitudes.…

High Energy Physics - Theory · Physics 2015-05-13 J. M. Drummond , J. Henn , G. P. Korchemsky , E. Sokatchev

We present a program for the numerical evaluation of scalar integrals and tensor form factors entering the calculation of one-loop amplitudes which supports the use of complex masses in the loop integrals. The program is built on an earlier…

High Energy Physics - Phenomenology · Physics 2015-05-27 G. Cullen , J. -Ph. Guillet , G. Heinrich , T. Kleinschmidt , E. Pilon , T. Reiter , M. Rodgers

We use a graphics processing unit (GPU) for fast calculations of helicity amplitudes of quark and gluon scattering processes in massless QCD. New HEGET ({\bf H}ELAS {\bf E}valuation with {\bf G}PU {\bf E}nhanced {\bf T}echnology) codes for…

High Energy Physics - Phenomenology · Physics 2011-02-09 K. Hagiwara , J. Kanzaki , N. Okamura , D. Rainwater , T. Stelzer

In this paper, we give the general expressions for a special series of tree amplitudes of the Yang-Mills theory. This series of amplitudes have two adjacent massless spin-1 particles with extra-dimensional momenta and any number of positive…

High Energy Physics - Theory · Physics 2019-10-08 Yang An , Yi Li

NLO scattering amplitudes are provided by fully automated numerical tools, such as OpenLoops, for a very wide range of processes. In order to match the numerical precision of current and future collider experiments, the higher precision of…

High Energy Physics - Phenomenology · Physics 2022-07-18 Stefano Pozzorini , Natalie Schär , Max F. Zoller

This thesis is focused on the development of new mathematical methods for computing multi-loop scattering amplitudes in gauge theories. In this work we combine, for the first time, the unitarity-based construction for integrands, and the…

High Energy Physics - Phenomenology · Physics 2014-10-21 Ulrich Schubert

We establish a connection between tree-level superamplitudes in ABJM theory and leading singularities associated to special three-particle cuts of one-loop superamplitudes where one of the tree amplitudes entering the cut is a four-point…

High Energy Physics - Theory · Physics 2017-08-23 Andreas Brandhuber , Gabriele Travaglini , Congkao Wen