A new approach to semi-inclusive deep-inelastic scattering with QED and QCD factorization

We present the details of a new factorized approach to semi-inclusive deep-inelastic scattering which treats QED and QCD radiation on equal footing, and provides a systematically improvable approximation to the extraction of transverse momentum dependent parton distributions. We demonstrate how the QED contributions can be well approximated by collinear factorization, and illustrate the application of the factorized approach to QED radiation in inclusive scattering. For semi-inclusive processes, we show how radiation effects prevent a well-defined photon-nucleon frame, forcing one to use a two-step process to account for the radiation. We illustrate the utility of the new method by explicit application to the spin-dependent Sivers and Collins asymmetries.

Automated summary

This paper introduces a new factorized approach to semi-inclusive deep-inelastic scattering, treating QED and QCD radiation equally, and providing a systematically improvable approximation to the extraction of transverse momentum dependent parton distributions. It demonstrates the approximation of QED contributions through collinear factorization, and illustrates its application in inclusive scattering, as well as how radiation effects impact the photon-nucleon frame in semi-inclusive processes. The utility of the new method is illustrated through explicit application to spin-dependent Sivers and Collins asymmetries.