Opportunities for Imaging Light Nuclei with a Second Interaction Region at the Electron-Ion Collider

TL;DR

This paper explores the potential of a second interaction region at the Electron-Ion Collider to enhance imaging of light nuclei through diffractive processes, expanding the collider's scientific capabilities.

Contribution

It presents an exploratory study of detection capabilities for light nuclei at a second EIC interaction region, highlighting its benefits for nuclear imaging.

Findings

Enhanced forward acceptance improves detection of small-angle scattering.

Mapping spatial parton distributions in light nuclei is feasible.

Second interaction region complements the main detector for diverse physics programs.

Abstract

The upcoming Electron-Ion Collider (EIC) will address several outstanding puzzles in modern nuclear physics. Key questions-such as the partonic structure of nucleons and nuclei and the origin of their mass and spin-can be explored through high-energy electron-proton and electron-nucleus collisions. To maximize its scientific reach, the EIC community has advocated for the addition of a second interaction region equipped with a detector complementary to the EIC general purpose collider detector, ePIC. The pre-conceptual design of this interaction region aims to provide a different configuration from the first interaction region, which enhances forward acceptance at very small scattering angles ($\theta \sim 0$ mrad). This machine configuration would significantly benefit exclusive, tagging, and diffractive physics programs, complementing those of the ePIC experiment. In particular, accessing coherent diffractive processes on light nuclei by tagging of the full, intact nucleus is essential for mapping their spatial parton distributions. In this work, we present an exploratory study of the detection capabilities for light nuclei at a second EIC interaction region, with a detailed discussion of the accessible kinematic phase space and its implications for imaging.