Infrared subtraction at next-to-next-to-leading order for gluonic initial states

Abstract

In this thesis we describe a procedure for isolating the infrared singularities present in gluonic scattering amplitudes at
next-to-leading and next-to-next-to-leading order. We adopted the
antenna subtraction framework which has been successfully applied to the
calculation of NNLO corrections to the 3-jet cross section and related
event shape distributions in electron-positron annihilation. We consider
processes with coloured particles in the initial state, and in
particular two-jet production in hadron-hadron collisions at
accelerators such as the Large Hadron Collider (LHC). We derive explicit
formulae for subtracting the single and double unresolved contributions
from the double radiation gluonic processes using
antenna functions with initial state partons. We show numerically that
the subtraction term effectively approximates the matrix element in the
various single and double unresolved configurations.