Hadronic Physics for Fundamental Discoveries

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Nuclear and particle physics aim to understand fundamental parameters and laws of nature at subatomic distances. Among such parameters are the masses of elementary particles: quarks and leptons. Quarks are particles that interact via the strong force -- this force binds them together in an atomic nucleus. Leptons do not feel this force; the most familiar example of a lepton is the electron that is bound to the nucleus by the electromagnetic interaction. A more exotic lepton is the neutrino, which has no electric charge and interacts only weakly. Yet, this elusive particle is proving to be a crucial link in our search for new physics. Exquisite experimental measurements over the last two decades have revealed that the neutrinos have small but nonzero masses, but the fundamental understanding of the quarks and lepton masses remains elusive. In this broader context, this project will provide the theoretical foundations needed in support of experimental efforts designed to measure with high accuracy the masses of the neutrinos and light quarks. This project will provide excellent training ground for students.An important challenge in nuclear and particle physics concerns the description of the strong force at low energy with the accuracy matching the experimental level of precision. Specifically, the aim of this project is to understand the three-pion system. This system is the final state of the decay of the eta-meson that is used for the light quark mass determination.This system is also an intermediate state of the neutrino-nucleus interaction and therefore plays an essential role in interpreting neutrino experiments. The PI and her collaborators will develop an analytical framework to accurately model three-pion interactions, based on the methods of chiral perturbation theory and dispersive techniques. This will support state-of-the-art nuclear physics experiments at Thomas Jefferson Laboratory, particularly GlueX or CLAS, as well as the upcoming precision neutrino-nucleus scattering experiments at Fermilab and worldwide.