Spatial imaging of polarized deuterons at the Electron-Ion Collider

TL;DR

This paper investigates how the polarization of deuterons affects diffractive vector meson production at small-$x$ in electron-deuteron collisions, revealing polarization-dependent angular distributions and saturation effects relevant for future Electron-Ion Collider experiments.

Contribution

It introduces a detailed analysis of polarization effects on the deuteron wave function and gluon saturation in small-$x$ vector meson production, providing new insights into polarized nuclear structure.

Findings

Azimuthal angular dependence varies with deuteron polarization.

Effective deuteron radius shows polarization-dependent behavior.

Gluon saturation effects are slightly enhanced in longitudinal polarization.

Abstract

We study diffractive vector meson production at small-$x$ in the collision of electrons and polarized deuterons $e+d^{\uparrow}$. We consider the polarization dependence of the nuclear wave function of the deuteron, which results in an azimuthal angular dependence of the produced vector meson when the deuteron is transversely polarized. The Fourier coefficients extracted from the azimuthal angular dependence of the vector meson differential cross-section exhibit notable differences between longitudinally and transversely polarized deuterons. The angular dependence of the extracted effective deuteron radius provides direct insight into the structure of the polarized deuteron wave function. Furthermore, we observe slightly increased gluon saturation effects when the deuteron is longitudinally polarized compared to the transversely polarized case. The small-$x$ observables studied in this work will be accessible at the future Electron-Ion Collider.