The Belle II Collaboration

30 March 2022

Abstract: We reconstruct clean samples of π0 → γγ decays from the D∗+ → D0(→ K−π+π0)π+ decay chain in both data and simulation to study the bias in the reconstructed π0 mass. We use the data collected by Belle II during 2019, 2020 and the first half of 2021 which correspond to 207 fb−1 of integrated luminosity. The results from the data are compared to run-dependent and run-independent official Belle II simulations. The study is performed as a function of the photons’ energies and polar angles.