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arXiv · 2303.08354

Measurement of the branching fraction and $\it CP$ asymmetry of $B^{0} \rightarrow \pi^{0} \pi^{0}$ decays using $198 \times 10^6$ $B\overline{B}$ pairs in Belle II data

Belle II Collaboration·F. Abudinén·I. Adachi·K. Adamczyk·L. Aggarwal·H. Ahmed·H. Aihara·N. Akopov·A. Aloisio·N. Anh Ky·D. M. Asner·H. Atmacan·T. Aushev·V. Aushev·H. Bae·S. Bahinipati·P. Bambade·Sw. Banerjee·S. Bansal·M. Barrett·J. Baudot·M. Bauer·A. Baur·A. Beaubien·J. Becker·P. K. Behera·J. V. Bennett·E. Bernieri·F. U. Bernlochner·V. Bertacchi·M. Bertemes·E. Bertholet·M. Bessner·S. Bettarini·V. Bhardwaj·B. Bhuyan·F. Bianchi·T. Bilka·S. Bilokin·D. Biswas·D. Bodrov·A. Bolz·J. Borah·A. Bozek·M. Bračko·P. Branchini·R. A. Briere·T. E. Browder·A. Budano·S. Bussino·M. Campajola·L. Cao·G. Casarosa·C. Cecchi·M. -C. Chang·P. Chang·R. Cheaib·P. Cheema·V. Chekelian·C. Chen·Y. Q. Chen·B. G. Cheon·K. Chilikin·K. Chirapatpimol·H. -E. Cho·K. Cho·S. -J. Cho·S. -K. Choi·S. Choudhury·D. Cinabro·J. Cochran·L. Corona·S. Cunliffe·S. Das·F. Dattola·E. De La Cruz-Burelo·S. A. De La Motte·G. de Marino·G. De Nardo·M. De Nuccio·G. De Pietro·R. de Sangro·M. Destefanis·S. Dey·A. De Yta-Hernandez·R. Dhamija·A. Di Canto·F. Di Capua·Z. Doležal·I. Domínguez Jiménez·T. V. Dong·M. Dorigo·K. Dort·D. Dossett·S. Dreyer·S. Dubey·G. Dujany·P. Ecker·M. Eliachevitch·P. Feichtinger
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Abstract

We report measurements of the branching fraction and $\it CP$ asymmetry in $B^{0} \to \pi^{0} \pi^{0}$ decays reconstructed at Belle II in an electron-positron collision sample containing $198 \times 10^{6}$ $B\overline{B}$ pairs. We measure a branching fraction $\mathcal{B}(\Bpipi) = (1.38 \pm 0.27 \pm 0.22) \times 10^{-6}$ and a $\it CP$ asymmetry $\Acp(\Bpipi) = 0.14 \pm 0.46 \pm 0.07$, where the first uncertainty is statistical and the second is systematic.

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Belle II Collaboration, F. Abudinén, I. Adachi, K. Adamczyk, L. Aggarwal, H. Ahmed, H. Aihara, N. Akopov, A. Aloisio, N. Anh Ky, D. M. Asner, H. Atmacan, T. Aushev, V. Aushev, H. Bae, S. Bahinipati, P. Bambade, Sw. Banerjee, S. Bansal, M. Barrett, J. Baudot, M. Bauer, A. Baur, A. Beaubien, J. Becker, P. K. Behera, J. V. Bennett, E. Bernieri, F. U. Bernlochner, V. Bertacchi, M. Bertemes, E. Bertholet, M. Bessner, S. Bettarini, V. Bhardwaj, B. Bhuyan, F. Bianchi, T. Bilka, S. Bilokin, D. Biswas, D. Bodrov, A. Bolz, J. Borah, A. Bozek, M. Bračko, P. Branchini, R. A. Briere, T. E. Browder, A. Budano, S. Bussino, M. Campajola, L. Cao, G. Casarosa, C. Cecchi, M. -C. Chang, P. Chang, R. Cheaib, P. Cheema, V. Chekelian, C. Chen, Y. Q. Chen, B. G. Cheon, K. Chilikin, K. Chirapatpimol, H. -E. Cho, K. Cho, S. -J. Cho, S. -K. Choi, S. Choudhury, D. Cinabro, J. Cochran, L. Corona, S. Cunliffe, S. Das, F. Dattola, E. De La Cruz-Burelo, S. A. De La Motte, G. de Marino, G. De Nardo, M. De Nuccio, G. De Pietro, R. de Sangro, M. Destefanis, S. Dey, A. De Yta-Hernandez, R. Dhamija, A. Di Canto, F. Di Capua, Z. Doležal, I. Domínguez Jiménez, T. V. Dong, M. Dorigo, K. Dort, D. Dossett, S. Dreyer, S. Dubey, G. Dujany, P. Ecker, M. Eliachevitch, P. Feichtinger. 2023-03-15. Measurement of the branching fraction and $\it CP$ asymmetry of $B^{0} \rightarrow \pi^{0} \pi^{0}$ decays using $198 \times 10^6$ $B\overline{B}$ pairs in Belle II data. https://doi.org/10.1103/physrevd.107.112009

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