Phys. Rev. D 109, 012001 (2024)

ISSN: 2470-0010, SCIE

Measurement of branching fractions and direct C P asymmetries for B → K π and B → π π decays at Belle II

Belle II Collaboration (I. Adachi, ..., N. Anh Ky, ...)

We report measurements of the branching fractions and direct CP asymmetries of the decays B0 → Kþπ−, Bþ → Kþπ0, Bþ → K0πþ, and B0 → K0π0, and use these for testing the standard model through an isospin-based sum rule. In addition, we measure the branching fraction and direct CP asymmetry of the decay Bþ → πþπ0 and the branching fraction of the decay B0 → πþπ−. The data are collected with the Belle II detector from eþe− collisions at the ϒð4SÞ resonance produced by the SuperKEKB asymmetric-energy collider and contain 387 × 106 bottom-antibottom meson pairs. Signal yields are determined in two-dimensional fits to background-discriminating variables, and range from 500 to 3900 decays, depending on the channel. We obtain −0.03 0.13 0.04 for the sum rule in agreement with the standard model expectation of zero and with a precision comparable to the best existing determinations.

DOI: https://doi.org/10.1103/PhysRevD.109.012001