Elucidating the Fundamental Properties of the Nucleon with Dispersive Techniques

Indiana University, Bloomington IN

Investigators

Abstract

Modern nuclear physics and particle physics are concerned with understanding the fundamental parameters and symmetries of nature. A crucial new piece of this puzzle has recently become available with the Nobel-prize-winning discovery of the neutrino flavor oscillations, which showed that neutrinos had masses contrary to the paradigm of the Standard Model. Today, the field of neutrino physics enters the precision era, with accelerator-based neutrino oscillation experiments taking center stage in the experimental program in the US and in the world. To understand neutrino interactions with nuclei in the detector requires accurate modeling of strong interactions—the force that binds the nucleus together. The PI will do this using state-of-the-art analytical techniques, focusing on the quantities of most direct relevance to neutrino experiments at Fermilab and elsewhere. This project will thus provide the necessary theoretical foundations needed to support these experimental breakthroughs. It will also provide excellent training ground for students and young researchers. The focus of this project is be on a specific piece of physics that plays a crucial role in modeling neutrino interactions at GeV energies: the nucleon axial form factor. It describes the structure of the nucleon which is not a point-like particle but has a structure that is still not well known. The PI and her collaborators will develop a physics-based framework to accurately model this form factor, based on the methods of chiral perturbation theory and dispersive techniques. Moreover, a bridge to numerical evaluations on the lattice will be established by applications of various analytical constraints, such as current conservation. Agreement with various electron scattering data will also be explored. 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. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.