RUI: Studies of Heavy Quarkonium Spectroscopy with Belle and Belle II

The spectroscopy of Heavy Quarkonium is generally regarded as an excellent laboratory for understanding Quantum Chromodynamics (QCD), the quantum theory of strong interactions. A renaissance of quarkonium spectroscopy came with experiments including CLEO, CLEO-c, Belle and Belle II, with which the PI of this program has been engaged for twenty-five years. The Belle and Belle II Experiments at KEK in Japan have collected the world's largest data samples at the bottomonium resonances, the so-called Upsilon resonances. These samples have allowed experimenters to acquire large statistics for observing the decays of bottomonium, open bottom, and open charm mesons, and thereby study important questions of heavy flavor physics and of rare phenomena in these decays, including potentially New Physics. The central aim of this RUI program of research by the Luther College group is to study the spectroscopy of bottomonium and bottomonium-like mesons like the exotic four-quark Zb states, with a focus on resonant states that probe the limits of our understanding of Quantum Chromodynamics (QCD), and of states whose quark content cannot be either three quarks or a quark and antiquark. The Luther College program provides an unusual opportunity for undergraduate students to become meaningfully involved in a world-leading experiment, taking part in every aspect of Belle and Belle II data analysis, and to support the operation of the upgraded experiment, Belle II. The broader impacts of the program focus on bringing the exciting world of elementary particle physics and scientific research to audiences including students and teachers both in the rural northeast quarter of Iowa, but also surrounding areas in the region including western Wisconsin and southern Minnesota through classroom visits, student STEM fair programs, and other activities. Outreach efforts include bringing International Master Classes for high school and middle school students in the region, through STEM-related classes in the Dorian Music camps which reach over 600 students each summer at Luther College, and go considerably beyond, as the PI is co-chair of the Belle II Outreach group which oversees social media and outreach to teachers and students on behalf of the Collaboration. 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.