An overall description of the research in this project is the study of proton structure (or more generally, of the structure of particles that feels the nuclear force, collectively known as hadrons). We want to learn the details of how the proton is put together, or how matter is distributed within a proton, and also to make use of this knowledge in the related fields, such as atomic physics, to calculate phenomena that are sensitive to the proton size. One remarkable method we use is a mathematical equivalence between results obtained in certain weakly coupled, hence relatively easily calculable, 5-dimensional theories and results in the 4-dimensional (counting time) theories that describe our world. We obtain results this way for the charge distribution, magnetization distribution, and energy distribution inside the proton and other particles. We have also been able to apply our knowledge of proton structure to make calculation of splittings between certain hydrogen energy levels to the remarkable accuracy of a part in a million.
The direct impact of this research is to further our understanding of forefront hadronic physics. Broader impacts of the proposed activity include the training of new students, including undergraduates; bridging the gaps between different fields of physics such as between atomic and nuclear physics; and, given that the principal investigator is regularly at the Jefferson Laboratory, bridging the gap between university and national lab research groups. The principle investigator, it may be also noted, has had two successful women Ph. D. students and there may be further opportunities along these lines.
