The Electron-Ion Collider: A Second Interaction Region and its Opportunity

The Electron-Ion Collider (EIC) is the next large-scale nuclear physics project in the US. The unique and powerful tools of the EIC will peer into protons and neutrons, the building blocks that make up atomic nuclei, providing unprecedented insight into how those particles’ internal building blocks - and the gluelike force that holds them together - build up the structure of nearly all visible matter in the Universe.

Scientists around the world are working to design detector systems that will make the most of the EIC’s technical capabilities. Ideally, EIC scientists would like to build two complementary detectors so they can collect different kinds of data and/or cross-check one another’s findings. The Brookhaven National Lab’s collider complex has two interaction regions for such large-scale EIC detectors. The EIC project within the DOE Office of Science includes funding for the accelerators, one interaction region, and one detector.

The EIC User Community is in strong support of a second complementary detector and is endorsed by an advisory panel (DPAP) that made a strong case for two complementary general-purpose detectors.

A second detector will enable one to examine the physics of the EIC case in a complementary fashion but also provides the opportunity to follow a path to new ideas. We will discuss in this presentation the benefits and opportunities as well as the challenges a second detector will supply within the EIC.