Measuring Gluon Sivers Function at a Future Electron-Ion Collider

Liang Zheng,J H Lee,Bo-Wen Xiao,E C Aschenauer,Zhong-Bao Yin

doi:10.1142/s2010194518600212

Abstract

In this work, we present a systematic study on the feasibility of probing the largely unexplored gluon Sivers function (GSF) based on the open charm production, charged dihadron and dijet method at a future high energy, high luminosity Electron-Ion Collider (EIC). Sivers function describes the anisotropy of parton distributions inside a transversely polarized nucleon in the momentum space and provides us a complete picture of the 2+1D structure of the nucleons. It is proposed that the GSF can be studied through the single spin asymmetry (SSA) measurement in the photon-gluon fusion channel with electron proton collisions at the EIC. Using a well tuned Monte Carlo model for deep inelastic scatterings, we estimate the possible constraints of the gluon Sivers effect one can draw from the future EIC data. Comparisons of all the possible measurements further illustrate that the dijet method is the most promising way to demonstrate the presence of GSF and pin down its evolution effect.

Highlights

In recent years, an important quest in hadron physics is to explore the multidimensional structure of the nucleon based on the partonic degrees of freedom
We provide an estimate to the possible size of single spin asymmetry in the following studies with three model assumptions
As the kinematics of a directly generated D0 is of little difference compared to that of a heavier D meson state generating it, we include all the D0 in our study

Summary

Introduction

An important quest in hadron physics is to explore the multidimensional structure of the nucleon based on the partonic degrees of freedom. It has been shown in Ref. 8, 9 that gluon transverse momentum distribution can be mapped through quark-antiquark jet correlation in deep inelastic scattering (DIS). The open charm production in electron-proton scattering ep↑ → e ccX, for instance, is supposed to be a direct probe to the gluon Sivers effect 6.

Results

Conclusion