Two-loop QCD helicity amplitudes for massless quark-quark scattering

2004/01/31 by E. W. N. Glover
Mathematics · Physics and Astronomy · #Amplitude #Helicity #High-Energy Particle Collisions Research #Loop (graph theory) #Massless particle #Mathematical physics #Mathematics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum electrodynamics #Quantum mechanics #Quark #Renormalization #Scattering amplitude #hep-ph

paper · pdf · doi:10.1088/1126-6708/2004/04/021

published as JHEP0404:021,2004 · Latex, JHEP3 class, 68 pages, typos corrected, reference added

openalex publication_date 2004/04/14 · arxiv created 2004/09/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We present the two-loop helicity amplitudes for the scattering of massless quarks in QCD. We use projector techniques to compute the coefficients of the general four-quark amplitude at up to two-loops in conventional dimensional regularisation and use these coefficients to derive the helicity amplitudes in the 't Hooft-Veltman scheme. The structure of the infrared divergences agrees with that predicted by Catani while expressions for the finite remainders for q q → Q Q and the processes related by crossing symmetry are given in terms of logarithms and polylogarithms that are real in the physical region. We have checked that the interference of tree and two-loop helicity amplitudes, summed over helicities and colours, reproduces the previous results for the finite remainders for interference of tree and two-loop amplitudes given in Refs. [1,2].

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