2009/07/28 by Andrea Ferroglia, Matthias Neubert, Ben D. Pecjak +1 · 165 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Factorization #Massless particle #Mathematical physics #Particle physics #Particle physics theoretical and experimental studies #Parton #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Resummation #Scattering #Scattering amplitude #hep-ph
paper · pdf · doi:10.1103/physrevlett.103.201601
published in Physical Review Letters 103(20), 201601 (American Physical Society) · 4 pages, 1 figure
arxiv created 2009/07/28 · openalex publication_date 2009/11/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We provide a complete description of the two-loop infrared singularities of scattering amplitudes with an arbitrary number of massive and massless partons in non-Abelian gauge theories. To this end, we calculate the two universal functions that completely specify the structure of three-parton correlations in the soft anomalous-dimension matrix at two-loop order in closed analytic form. Both functions are found to be suppressed like O(m(4)/s(2)) in the limit of small parton masses, in accordance with mass factorization theorems. On the other hand, they are unsuppressed near the threshold for pair production of two heavy particles. As an application, we calculate the two-loop anomalous-dimension matrix for qq --> tt near threshold and show that it is not diagonal in the s-channel singlet-octet basis.