Intrinsic transverse parton momenta in deeply inelastic reactions

TL;DR

This paper reviews the current understanding of intrinsic transverse parton momenta in deep-inelastic scattering and Drell-Yan processes, confirming the effectiveness of the Gaussian model and supporting the factorization approach.

Contribution

It provides an updated assessment of pT distributions, validating the Gaussian model and demonstrating compatibility of intrinsic momenta in SIDIS and DY.

Findings

Gaussian model fits pT-distributions well

Intrinsic pT in SIDIS and DY are compatible

Energy dependence of pT can be practically modeled

Abstract

Intrinsic transverse parton momenta pT play an important role in the understanding of azimuthal/spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) and the Drell-Yan process (DY). We review and update what is presently known about pT from these processes. In particular, we address the question to which extent data support the popular Gauss model for the pT-distributions. We find that the Gauss model works very well, and observe that the intrinsic transverse momenta in SIDIS and DY are compatible, which is a support for the factorization approach. As a byproduct we recover a simple but practical way of taking into account the energy dependence of pT-distributions.