Transverse Momentum Dependent Parton Distribution/Fragmentation Functions at an Electron-Ion Collider

TL;DR

This paper reviews theoretical and experimental aspects of transverse momentum dependent parton distribution functions (TMDs) at a future electron-ion collider, highlighting the potential to explore quark-gluon interactions and partonic structure through SSA measurements.

Contribution

It provides a comprehensive summary of recent workshop discussions on TMDs, including simulation results and experimental requirements for studying partonic correlations at an EIC.

Findings

SSA measurements in SIDIS are crucial for TMD studies in sea and valence quarks.

Simulation results support the feasibility of TMD measurements at an EIC.

Exploration of tri-gluon correlations via SSA in D meson production.

Abstract

We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse momentum dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. We then present simulation results on experimental studies of TMDs through measurements of single spin asymmetries (SSA) from semi-inclusive deep-inelastic scattering (SIDIS) processes with an EIC, and discuss the requirement of the detector for SIDIS measurements. The dynamics of parton correlations in the nucleon is further explored via a study of SSA in D (`D) production at large transverse momenta with the aim of accessing the unexplored tri-gluon correlation functions. The workshop participants identified the SSA measurements in SIDIS as a golden program to study TMDs in both the sea and valence quark regions and to study the role of gluons, with the Sivers asymmetry measurements as examples. Such measurements will lead to major advancement in our understanding of TMDs in the valence quark region, and more importantly also allow for the investigation of TMDs in the sea quark region along with a study of their evolution.