Towards three-dimensional nucleon structures at the Electron-Ion Collider in China: A study of the Sivers function

TL;DR

This study explores how future measurements at the Electron-Ion Collider in China can improve the understanding of the Sivers function, a key component in three-dimensional nucleon structure, through combined analysis of existing and simulated data.

Contribution

It demonstrates that EicC data will enable precise extraction of the Sivers function for various quark flavors, especially sea quarks, in the relevant momentum region.

Findings

EicC data significantly improves Sivers function determination.

Sea quark Sivers functions can be precisely extracted.

Combined analysis reduces uncertainties in TMDs.

Abstract

Transverse momentum-dependent parton distribution functions (TMDs) provide three-dimensional imaging of the nucleon in the momentum space. With its fundamental importance in understanding the spin structure of the nucleon, the precise measurement of TMDs is considered as one of the main physics topics of the proposed Electron-Ion Collider in China (EicC). In this paper, we investigate the impact of future semi-inclusive deep inelastic scattering (SIDIS) data from EicC on the extraction of TMDs. Taking the Sivers function as an example, we revisited the world SIDIS data, which serves as the input for the simulated EicC data. By performing a combined analysis of the world data and the EicC simulated data, we quantitatively demonstrate that the Sivers functions can be precisely determined for various quark flavors, especially for sea quarks, in the region, $x>0.005$, directly covered by the EicC.