RBRC Seminar

Abstract: Heavy-ion collision experiments have lead to a picture of high-energy nuclear scattering in which nuclei are treated as batches of nucleons that determine, event-to-event, the snapshot of the interacting matter and the energy density deposited in space. One way or another, modeling the structure of the colliding nucleons is part of this picture. Observables in nucleus-nucleus collisions show typically mild sensitivity to the details of the nucleon structure, such that the latter has been mainly discussed in the context of small collision systems.

In this seminar, I show that nucleon structure plays in fact an important role as well in large systems. I review the history of the implementation of nucleons in A-A collisions, pointing out the inconsistencies that exist among state-of-the-art simulation frameworks. I discuss, hence, what tools and observables can be used to resolve such inconsistencies in a data-driven way, posing emphasis on mean momentum-flow correlations, which are greatly sensitive to the sub-nucleonic length scale associated with the modeled nucleons.

Ensuring an implementation of nucleons consistent with A-A data has three major consequences. First, one can not hope to constrain the bulk viscosity of the quark-gluon plasma without it. Second, it allows us to gauge the geometry of p-p and p-A collisions from large systems alone, which are better understood. Third, it will permit us to link the information obtained in collisions of large nuclei to that obtained in future electron-ion collisions.