Chiara La Licata

24 May 2021
PHENO 2021

Abstract: sin2𝜙1 (sin2𝛽) is measured using the 𝐶𝑃-eigenstates induced by the 𝑏→𝑐 tree diagram and it is the most precise variable among the CKM angles. We have presented the result of the measurement using the 𝐵0→𝐽/𝜓𝐾0𝑆 decay collected from the early Belle II data. On the other hand, it can be measured also using the decays induced by 𝑏→𝑠 penguin diagram. In that case, contribution of the new physics is expected so that effective sin2𝜙1≡sin2𝜙eff1 is measured. In relation to those measurements, we present the re-discoveries of the 𝐵0→𝐽/𝜓𝐾0𝐿 and 𝐵0→𝜂′𝐾0𝑆 decays using the data set obtained by the Belle II in 2019 and 2020. Former one is a good indicator to check the difference of 𝐶𝑃 eigenvalue between 𝐵0→𝐽/𝜓𝐾0𝑆. Latter one is one of the modes used for sin2𝜙eff1 measurement and its branching fraction is relatively large.