Double-real corrections to color singlet decay in a parton-shower inspired scheme

Abstract

We introduce a local infrared subtraction method for next-to-next-to-leading order QCD calculations in color singlet decays, which is modeled on the evolution algorithm of a parton shower. Overlapping singularities in the multipole radiation pattern are disentangled by partial fractioning, and the kinematics mapping corresponds to iterated next-to-leading order kinematics. We verify that the double-real remainder to $e^{+}{e}^{-}\to q\bar{q}$ is rendered finite in the single and double unresolved limits and investigate the numerical convergence of the Monte-Carlo integral. We compute the phase-space integrals of the scalar counterterms in the back-to-back configuration, both analytically and with the help of numerical techniques based on sector decomposition.

Comments: 19 pages, 4 figures