Measurements of CP asymmetries in D0 → π +π −π 0 decays in Dalitz plot regions at Belle II

We perform a search for charge-parity violation (CPV) in the density of events in a binned Dalitz plot of D^∗ -tagged D⁰ → π⁺π⁻π⁰ decays. The data used for this analysis is 362 fb⁻¹ of Υ(4S) data collected at Belle II from 2019–2022. We develop a novel binned Dalitz analysis method to determine local CPV; our method carefully accounts for nuisance asymmetries not due to CPV using the data itself rather than relying on simulations. All final asymmetry measurements are consistent with the no-CPV hypothesis. Our analysis method will scale well as Belle II collects more data, and we expect both the statistical and systematic uncertainties on the results to decrease if the analysis is redone on a larger dataset.