Fundamental QCD effects in Nuclei: The EMC Effect and Beyond

Nuclei are made of hadrons that behave in both well-determined and potentially mysterious ways in nuclei. Experimental nuclear physics has revealed hadronic effects that appear to require a range of energy scales to understand. One focus of this talk will be on the behavior of quarks in nucleons, with a particular emphasis on how quark behavior changes when nucleons are isolated vs. in a nuclear environment, and the implications of such changes. Quark behavior in nuclei is mysterious, it was discovered in 1983 and is dubbed the “EMC effect.” The EMC effect is a rather humble effect, it deviates by approximately 10-20% from the expected quark behavior. However, as we know from the history of physics, even the most humble of experimental results can become the threads that unwind into a revolution. I will discuss the frontiers of hadronic physics today, from diquarks to hexadiquarks to nucleon spin mysteries, antiquark flavor puzzles, tetraquarks and beyond.