We present a design for a high-granularity zero-degree calorimeter (ZDC) for
the upcoming Electron-Ion Collider (EIC). The design uses SiPM-on-tile
technology and features a novel staggered-layer arrangement that improves
spatial resolution. To fully leverage the design's high granularity and
non-trivial geometry, we employ graph neural networks (GNNs) for energy and
angle regression as well as signal classification. The GNN-boosted performance
metrics meet, and in some cases, significantly surpass the requirements set in
the EIC Yellow Report, laying the groundwork for enhanced measurements that
will facilitate a wide physics program. Our studies show that GNNs can
significantly enhance the performance of high-granularity CALICE-style
calorimeters by automating and optimizing the software compensation algorithms
required for these systems. This improvement holds true even in the case of
complicated geometries that pose challenges for image-based AI/ML methods.Comment: 9 pages, 9 figures. Code and datasets include