Hikaru Tanigawa ; Yutaka Ushiroda ; Kazutaka Sumisawa ; Koji Hara

14 September 2022

Abstract: We report a measurement of decay-time dependent CP-violating parameters in B0 → KS0KS0KS0 decays. We use $(198.0 \pm 3.0) \times 10^6\ \BB$ pairs collected at the \FourS resonance with the Belle II detector at the SuperKEKB asymmetric-energy $e^+e^-$ collider. The observed mixing-induced and direct \cp violation parameters are $\scp = -1.86\ _{-0.46}^{+0.91}~{\rm (stat)} \pm 0.09~{\rm (syst)}$ and $\acp = -0.22\ _{-0.27}^{+0.30}~{\rm (stat)} \pm 0.04~{\rm (syst)}$, respectively.