Time-Integrated Measurement of the Branching Fraction and Direct CP Asymmetry of B0 → KS0π0 Decay at Belle II

Sumitted to PubDB: 2024-04-08

Category: Master Thesis, Visibility: Public

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Authors	Shu-Ping Lin
Non-Belle II authors	Pao-Ti Chang
Date	Jan. 1, 2023
Belle II Number	BELLE2-MTHESIS-2024-009
Abstract	We report updated measurements of the branching ratio and the direct CP-violating asym- metry in B0 → KS0π0 decay at Belle II. The flavour information of the decay is obtained from the pair-produced neutral B partner Btag, and the direct CP asymmetry parame- ter is determined with the time-integrated method. We analyse the 2019-2022 Belle II data from e+e− collisions produced by the asymmetric-energy SuperKEKB collider at the Υ(4S) resonance. The data analysed contain 387 million BB pairs and correspond to an integrated luminosity of 362 fb−1. We obtain the branching fraction and the direct CP asymmetry B(B0 → K0π0) = (10.16 ± 0.65 ± 0.65) × 10−6, A(B0 → K0π0) = −0.06 ± 0.15 ± 0.05, where the first uncertainties are statistical and the second systematic. With other Belle II B → Kπ measurements of branching fractions and direct CP asymmetries, we compute the Kπ isospin sum rule to be IKπ = −0.03 ± 0.13 ± 0.05, which is in agreement with the standard model prediction of zero.
Conference	Taipei