Measurements of branching fractions and CP-violating charge asymmetries in charmless decays reconstructed in 2019--2020 Belle~II data

F Abudinén, I Adachi, R Adak, K Adamczyk… - arXiv preprint arXiv …, 2020 - arxiv.org
F Abudinén, I Adachi, R Adak, K Adamczyk, P Ahlburg, JK Ahn, H Aihara, N Akopov
arXiv preprint arXiv:2009.09452, 2020arxiv.org
We report on first measurements of branching fractions~($\mathcal {B} $) and CP-violating
charge asymmetries~($\mathcal {A} $) in charmless $ B $ decays at Belle~ II. We use a
sample of electron-positron collisions collected in 2019 and 2020 at the $\Upsilon (4S) $
resonance and corresponding to $34.6 $\, fb $^{-1} $ of integrated luminosity. We use
simulation to determine optimized event selections. The $\Delta E $ distributions of the
resulting samples, restricted in $ M_ {\rm bc} $, are fit to determine signal yields. Signal …
We report on first measurements of branching fractions~() and CP-violating charge asymmetries~() in charmless decays at Belle~II. We use a sample of electron-positron collisions collected in 2019 and 2020 at the resonance and corresponding to \,fb of integrated luminosity. We use simulation to determine optimized event selections. The distributions of the resulting samples, restricted in , are fit to determine signal yields. Signal yields are corrected for efficiencies determined from simulation and control data samples to obtain branching fractions and CP-violating asymmetries for flavour-specific channels. These are the first measurements in charmless decays reported by Belle~II. Results are compatible with known determinations and show detector performance comparable with the best Belle results offering a reliable basis to assess projections for future reach.
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