Snowmass 2021 Letter of Interest: QCD and Hadronization Studies at Belle II on behalf of the U.S. Belle II Collaboration

Due to the precise knowledge of the initial state and clean experimental environment, electronpositron annihilation data have historically been of utmost importance to study the hadronization of light and charm quarks. The record setting luminosities of the B-factories Belle and BaBar made groundbreaking measurements in this field possible. This trend will be continued by Belle II. Housed at the SuperKEKB facility at KEK in Tsukuba, Japan, Belle II is a significant upgrade of Belle and aims to record 50× the integrated luminosity of Belle over the next 10 years. This contribution will focus on two topics where Belle II will have a high impact. Studying the fragmentation of polarized and unpolarized light and charm quarks into hadrons as well as jets, and the measurement of hadronic cross-sections and transition form factors which are important inputs to constrain the theoretical uncertainty on the anomalous magnetic moment of the muon. As part of the Snowmass process, we invite anyone interested in these topics to join us in leveraging the massive data samples that will be available at Belle II.