Speaker
Description
The factorization theorems of quantum chromodynamics (QCD) apply equally well to most simple
quantum field theories that require renormalization but where direct calculations are much more
straightforward. Working with these simpler theories is convenient for stress-testing the limits of the
factorization program and for examining general properties of the parton density functions (pdfs) or
other correlation functions that might be necessary for a factorized description of a process. With
this view in mind, we review the steps of factorization in a real scalar Yukawa field theory for both
deep inelastic scattering (DIS) and semi-inclusive deep inelastic scattering (SIDIS) cross sections.
In the case of SIDIS, we illustrate how to separate the small transverse momentum region, where
transverse momentum dependent (TMD) pdfs are needed, from a purely collinear large transverse
momentum region, and we examine the influence of subleading power corrections. We also review
the steps for formulating TMD factorization in transverse coordinate space, and we study the
effect of transforming to the well-known b∗-scheme. Within the Yukawa theory, we investigate the
consequences of switching to a generalized parton model (GPM) approach, and compare with a fully
factorized approach. Our results highlight the need to address similar or analogous issues in QCD.
