The smallest fluid on earth

Sonderkolloquium SFB-TR 211

Prof. Dr. Bjoern P. Schenke

Brookhaven National Laboratory

Department of Physics and Astronomy, Stony Brook University

Prof. L. von Smekal

I will review recent developments in the field of high energy nuclear physics. After summarizing some important findings from multi-particle correlations in heavy ion collisions, I will discuss the stunning similarities between heavy ion collisions and much smaller collision systems, such as proton+proton and proton+heavy nucleus collisions. Matter created in all these systems appears to behave like an almost perfect fluid. Nevertheless, another important contribution to flow-like correlation signals can come from initial state momentum correlations, and can be computed in an effective theory of quantum chromo dynamics, the color glass condensate. Using this theory to determine the initial conditions for hydrodynamic simulations provides a framework that includes both initial and final state effects, allowing to reveal their relative importance in different systems. I will compare results to experimental data from the Relativistic Heavy Ion Collider's (RHIC) small system scan as well as small and large systems studied at the Large Hadron Collider (LHC) at CERN.
Future improvements regarding the inputs to the calculation, involving both the fluctuating spatial structure of protons and larger nuclei as well as their multi-parton distributions in momentum space, can be made using measurements at a future electron ion collider (EIC), to be built at Brookhaven National Laboratory.