We report on new time-dependent 𝐶𝑃 violation measurements using the full dataset of Belle II
collected between 2019-2022 and on improved analysis software. Hadronic penguin decays, which
proceed via a 𝑏 → 𝑞𝑞𝑠 transition, are loop dominated, and thus sensitive to new physics. in this
class, we measure the time-dependent 𝐶𝑃 violation parameters 𝐶𝐶𝑃 = −0.19 ± 0.08 ± 0.03 and
𝑆𝐶𝑃 = 0.67 ± 0.10 ± 0.04 in the decay 𝐵0 → 𝜂′𝐾0
𝑆 . In 𝑏 → 𝛾(𝑠, 𝑑) transitions, radiative penguin
decays, the mixing-induced 𝐶𝑃 violation is suppressed by the polarization of the photon. New
physics contributions could, however, lead to a sizable mixing-induced term. Here, we measure
𝐶𝐶𝑃 = 0.10 ± 0.13 ± 0.03 and 𝑆𝐶𝑃 = 0.00 ± 0.27 ± 0.04 in exclusive decays to 𝐵0 → 𝐾∗0𝛾 and
𝐶𝐶𝑃 = −0.06 ± 0.25 ± 0.07 and 𝑆𝐶𝑃 = 0.04 ± 0.45 ± 0.10 in inclusive 𝐵0 → 𝐾0
𝑆 𝜋0𝛾 decays
excluding a 𝐾∗0 mass-region. These measurements require a flavor tagging algorithm. A flavor
tagger based on a graph neural network was developed at Belle II. The increased effective tagging
efficiency of 𝜖𝑡 𝑎𝑔 = (37.40 ± 0.43 ± 0.34)% is validated on the channel 𝐵0 → 𝐽/𝜓𝐾0
𝑆 . The
measured values are 𝐶𝐶𝑃 = −0.035 ± 0.026 ± 0.012 and 𝑆𝐶𝑃 = 0.724 ± 0.035 ± 0.014.