First decay-time-dependent analysis of B 0 → K 0 S π 0 at Belle II

We report measurements of the branching fraction ( B ) and direct CP -violating asymmetry 93 ( A CP ) of the charmless decay B 0 → K 0 π 0 at Belle II. A sample of e + e − collisions, corresponding 94 to 189 . 8 fb − 1 of integrated luminosity, recorded at the Υ (4 S ) resonance is used for the first decay- 95 time-dependent analysis of these decays within the experiment. We reconstruct about 135 signal 96 candidates, and measure B ( B 0 → K 0 π 0 ) = [11 . 0 ± 1 . 2(stat) ± 1 . 0(syst)] × 10 − 6 and A CP ( B 0 → 97 K 0 π 0 ) = − 0 . 41 +0 . 30 − 0 . 32 (stat) ± 0 . 09(syst). 98