Charm Sivers function at EicC

TL;DR

This paper explores the theoretical and phenomenological aspects of the charm Sivers function at EicC, linking it to the spin-dependent odderon and assessing measurement feasibility through simulations.

Contribution

It introduces a framework connecting the Sivers function to the spin-dependent odderon in small-x physics and evaluates EicC's potential to measure this function.

Findings

EicC can effectively probe the charm Sivers function.

The Sivers function is linked to the spin-dependent QCD odderon.

Simulations show feasible measurement of the charm Sivers function at EicC.

Abstract

The Electron-Ion Collider in China (EicC) is pivotal in enhancing our knowledge of the internal structure of nucleons and nuclei, particularly through the study of transverse momentum-dependent parton distributions (TMDs). Among the leading-twist TMDs, the Sivers function is of particular interest, as it provides crucial insights into the spin and momentum structure of hadrons and plays a significant role in describing transverse single spin asymmetries (SSAs) in high-energy scatterings. In this study, we focus on the theoretical framework and phenomenological implications of the Sivers function in the context of small-x physics, where it is intricately connected to the spin-dependent QCD odderon, demonstrating that the SSA can be expressed in terms of transverse momentum-dependent factorization within the Color Glass Condensate effective theory. Furthermore, we present simulation results using PythiaeRHIC to assess the feasibility of measuring the charm quark Sivers function at EicC. The simulation outcomes suggest that EicC, with its unique kinematic coverage, offers distinct advantages for probing the Sivers function, which would provide compelling evidence for the existence of the elusive spin-dependent odderon.