One of the most difficult unanswered problems in nuclear and particle physics is how to understand systems in which the components are so tightly bound together that it is impossible to separate them, as occurs inside the proton and neutron and many other particles. This project is designed to explore several methods of obtaining definitive information from such complicated systems, so that one can understandand how they are put together and why they interact the way they do. For most of the approaches to be researched, the investigators initiated the development of the methods used here. This project emphasizes collaborative work with researchers at several other universities and laboratories. The educational component represents an important part of the work to be performed here. The project allows for the training of graduate and undergraduate students both on the analytical aspects of theory, and will also make possible the mentoring of these students for success in their future carreers in industry or academia.
This project includes six specific problems that will be studied, three each for the PI and co-PI in areas of their respective expertise, all related to the question of how to understand systems in which the component particles are so tightly bound that it is difficult or impossible to separate them, such as inside protons and neutrons. These specific problems are 1) how the proton and neutron would be assembled if the strong nuclear force that holds them together had a different number of interaction charges than the three in our universe; 2) how best to extract the maximal amount of information about their detailed internal structure from experiments; 3) how to compute their actual dynamical interactions in a strong-force theory that is a realistic simplified model of the one studied experimentally, and 4) how closely this idealized theory appears to mimic the real one, since much more can be computed exactly from the ideal than from the real theory; 5) how to simulate the structure of an atom, much smaller than conventional atoms, formed from particles (muons) that appear in cosmic rays, which is guaranteed to exist but has not yet been experimentally observed; and 6) using a connection between strongly-interacting theories and gravity in curved spacetimes to study systems in which the strongly-interacting particles have such a high ambient energy that they can be said to have a finite temperature.
