Precision Electromagnetic Calorimetry with EEEMCAL at EIC

One of the primary goals of twenty-first century physics is the quantitative understanding of the nature of strongly bound subatomic systems in terms of the fundamental structure and origin of matter. This has motivated the construction of a major, new electron microscope, the Electron-Ion Collider (EIC). The Electron Endcap Electro Magnetic Calorimeter (EEEMCAL) is key to determining the energy-momentum four vector of the scattered electron at the EIC. This is required to extract the spatial resolution and quark momentum fraction probed in the electron-ion scattering event as the target is smashed into pieces in deep inelastic scattering. In inclusive scattering, where only the scattered electron is detected in the final-state, the measurement is impossible without the EEEMCAL. Inclusive measurements on the proton will yield the gluon momentum and helicity distributions and on nuclei will provide critical data relevant to the question of whether the gluon momentum distribution saturates. Further, precision measurements over a large kinematic range on the quark and gluon momentum distributions in nuclei will be possible. The EEEMCAL also enables science programs closely connected to the imaging of the elusive 3D substructure of the proton. This new direction of "nuclear femtography" mirrors comparable evolution in other fields of science, where imaging physical systems has been key to gaining new insight. This talk will give an overview of the EEEMCAL and the science it enables.