2002/09/30 by André H. Hoang, Andre H. Hoang, Iain W. Stewart
Physics and Astronomy · #Black Holes and Theoretical Physics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.67.114020
published as Phys.Rev. D67 (2003) 114020 · 31 pages, 11 figs
arxiv created 2002/09/30 · openalex publication_date 2003/06/23 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
For nonrelativistic QCD the velocity renormalization group correlates the renormalization scales for ultrasoft, potential and soft degrees of freedom. Here we discuss the renormalization of operators by ultrasoft gluons. We show that renormalization of soft vertices can induce new operators, and also present a procedure for correctly subtracting divergences in mixed potential-ultrasoft graphs. Our results affect the running of the spin-independent potentials in QCD. The change for the NNLL tt cross section near threshold is very small, being at the \ensuremath\lesssim1% level and essentially independent of the energy. We also discuss implications for analyzing situations where mv2\ensuremath∼\ensuremathΛQCD.