Speaker
Description
The KLN theorem establishes that infrared divergences in parton‑model diagrams cancel when summed alongside diagrams that account for the simultaneous hard interaction of multiple partons within the same hadron. Meanwhile, it is well established that initial-state infrared poles and logarithms are governed by collinear factorisation. In this talk, I introduce a formalism where an initial-state implementation of KLN works hand in hand with collinear factorisation.
I will show that in this framework hadronic cross-sections can be expressed in terms of iterated discontinuities of Feynman diagrams and expanded in virtuality using standard expansion-by-regions techniques. The leading virtuality contribution will be shown to be equivalent to the MSbar parton model result through a universal scheme change. In turn, this enables the application of the Local Unitarity method to the computation of hadronic cross sections.
