Multi-scale Imaging of Nuclear Deformation at the Electron Ion Collider

TL;DR

This paper demonstrates that exclusive vector meson production at high energy in electron-ion collisions is highly sensitive to nuclear deformation across multiple length scales, offering a new way to probe nuclear structure at the Electron-Ion Collider.

Contribution

It introduces a framework to connect nuclear deformation effects with vector meson production observables, highlighting the potential of the Electron-Ion Collider to measure nuclear shape deformations directly.

Findings

Larger nuclear deformations increase incoherent vector meson production.

Different deformation parameters influence specific transverse momentum regions.

Deformation effects are distinguishable between different nuclei like ${ m {^{20}Ne}}$ and ${ m {^{16}O}}$.

Abstract

We show within the Color Glass Condensate framework that exclusive vector meson production at high energy is sensitive to the geometric deformation of the target nucleus at multiple length scales. Studying $e+$U collisions and varying the deformation of the uranium target, we demonstrate that larger deformations result in enhanced incoherent vector meson production cross sections. Further, different multipole deformation parameters affect different regions of transverse momentum transfer. Employing JIMWLK evolution to study the Bjorken-$x$ dependence of our results, we find that the ratio of incoherent to coherent cross sections decreases with decreasing $x$, largely independently of the quadrupole deformation of the target. Comparing results for the same process using ${\rm {^{20}Ne}}$ targets with ${\rm {^{16}O}}$ targets, we find that differences in deformation are clearly visible in the incoherent cross section. These findings show that certain observables at the Electron-Ion Collider are very sensitive to nuclear structure. Consequently, deformations need to be taken into account when interpreting experimental results. More importantly, this also means that $\vert t\vert$-differential diffractive vector meson production could become a powerful tool, enabling the most direct measurements of nuclear structure at different length scales, ranging from nuclear deformation at low $\vert t\vert$ to nucleon- and subnucleon-size scales at higher $\vert t\vert$.