2023/24 R.E. Bell Lecture

Electron Ion Collider (EIC) — the next QCD frontier
Study of the glue that binds us all

Abhay Deshpande

Department of Physics and Astronomy
Stony Brook University

Despite many decades of theoretical and experimental investigations, some of the most fundamental and profound questions in Quantum Chromodynamics (QCD) remain unanswered. Gluons — the carrier of the strong force — and their collective interactions are at the heart of most of these unanswered questions. For example, although we know protons since about a century, we do not understand how exactly does its spin and mass emerge from their constituents (quarks and gluons). An high enough energy the proton (or any nucleus) is expected to be dominated by gluons. The gluon density is expected to rise so much that a novel state of saturated gluonic matter some times called - Color Glass Condensate (CGC) - with rather exotic properties is expected to emerge.  However, conclusive experimental evidence for it remains illusive. Does such a state really exist? What are its properties? Possibilities to address these and other such questions led to the successful proposal to build the Electron Ion Collider (EIC).  It will be built using the existing infrastructure of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in the US and built jointly with Jefferson Lab. In this talk I will review the science case for the EIC and present the status of the project including the accelerator and detector design. I will also emphasize the international nature of the project and layout the desire and opportunity for substantial international contributions.