Precision Global Modeling of Exotic Hadrons

The strong nuclear force, responsible for binding protons and neutrons tightly together in the atomic nucleus, has long been understood at its core to be explained by the interactions of particles called "quarks" that form compounds called "hadrons". Until 2003, all hadrons appeared as compounds of a quark and an antiparticle quark (mesons) or three-quark compounds (baryons, like protons and neutrons). Since then, scores of "exotic" 4-quark or 5-quark hadrons have been discovered, but no simple picture has yet been developed that describes how they are assembled. This project continues the development of a promising universal model of exotic hadrons, the dynamical diquark model (DDM), which has successfully described a number of exotic hadrons as compounds in which the components themselves are bound two-quark subunits (diquarks). Recent work on this model has been to combine the diquark compounds with effects caused by the presence of two-meson components with which they can mix (the DDM diabatic extension). In this project the PI and his students will develop diabatic techniques for precise predictions of measurable properties for the full spectrum of exotic hadrons, including predictions of yet-unseen exotics. This project addresses three major scientific lines of inquiry and one of intense public interest: First, the project will build on prior work to describe the exotics sector using the diabatic dynamical diquark mode (DDM)l. Second, the PI will mentor a PhD student on including effects from two-meson states mixing that depend upon those states' spin quantum numbers, thus creating the most advanced model of exotics to date. Third, the PI will apply the diabatic DDM to study open-heavy-flavor exotics such as the recently observed doubly-charmed T_cc meson that contains two charm -- and no anti-charm -- quarks. In addition, this project will help address a critical shortage of high-school physics teachers in Arizona by leveraging the establishment of Arizona State University's first-in-the-nation online Bachelor of Science in Physics degree program. Under the PI's guidance an established Arizona high-school science teacher will have the opportunity to gains the skills necessary for physics teaching certification in Arizona. 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.