Measurement of time-dependent CP violation parameters in B⁰ → K_S⁰ π⁰ γ decays at Belle and Belle II

@misc{belle2026measurement,
  title = {{Measurement of time-dependent $CP$ violation parameters in $B^0 \to K_S^0 π^0 γ$ decays at Belle and Belle II}},
  author = {Belle and Belle II Collaborations and M. Abumusabh and I. Adachi and A. Aggarwal and Y. Ahn and H. Aihara and M. Akdag and N. Akopov and S. Alghamdi and M. Alhakami and N. Althubiti and K. Amos and M. Angelsmark and N. Anh Ky and C. Antonioli and K. Arai and H. Atmacan and T. Aushev and V. Aushev and R. Ayad and V. Babu and H. Bae and N. K. Baghel and S. Bahinipati and P. Bambade and Sw. Banerjee and S. Bansal and M. Barrett and M. Bartl and J. Baudot and A. Beaubien and F. Becherer and J. Becker and G. F. Benfratello and J. V. Bennett and F. U. Bernlochner and V. Bertacchi and M. Bertemes and E. Bertholet and M. Bessner and S. Bettarini and V. Bhardwaj and B. Bhuyan and F. Bianchi and T. Bilka and D. Biswas and A. Bobrov and D. Bodrov and A. Bondar and G. Bonvicini and J. Borah and A. Boschetti and A. Bozek and M. Bračko and P. Branchini and N. Brenny and R. A. Briere and T. E. Browder and A. Budano},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2606.04496},
  eprint = {2606.04496},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.04496},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Measurement of time-dependent CP violation parameters in B^0 → K_S^0 π^0 γ decays at Belle and Belle II
AU  - Belle
AU  - Belle II Collaborations
AU  - M. Abumusabh
AU  - I. Adachi
AU  - A. Aggarwal
AU  - Y. Ahn
AU  - H. Aihara
AU  - M. Akdag
AU  - N. Akopov
AU  - S. Alghamdi
AU  - M. Alhakami
AU  - N. Althubiti
AU  - K. Amos
AU  - M. Angelsmark
AU  - N. Anh Ky
AU  - C. Antonioli
AU  - K. Arai
AU  - H. Atmacan
AU  - T. Aushev
AU  - V. Aushev
AU  - R. Ayad
AU  - V. Babu
AU  - H. Bae
AU  - N. K. Baghel
AU  - S. Bahinipati
AU  - P. Bambade
AU  - Sw. Banerjee
AU  - S. Bansal
AU  - M. Barrett
AU  - M. Bartl
AU  - J. Baudot
AU  - A. Beaubien
AU  - F. Becherer
AU  - J. Becker
AU  - G. F. Benfratello
AU  - J. V. Bennett
AU  - F. U. Bernlochner
AU  - V. Bertacchi
AU  - M. Bertemes
AU  - E. Bertholet
AU  - M. Bessner
AU  - S. Bettarini
AU  - V. Bhardwaj
AU  - B. Bhuyan
AU  - F. Bianchi
AU  - T. Bilka
AU  - D. Biswas
AU  - A. Bobrov
AU  - D. Bodrov
AU  - A. Bondar
AU  - G. Bonvicini
AU  - J. Borah
AU  - A. Boschetti
AU  - A. Bozek
AU  - M. Bračko
AU  - P. Branchini
AU  - N. Brenny
AU  - R. A. Briere
AU  - T. E. Browder
AU  - A. Budano
PY  - 2026
DA  - 2026/09/29
PB  - arXiv
DO  - 10.48550/arxiv.2606.04496
UR  - https://arxiv.org/abs/2606.04496
AB  - We perform a measurement of time-dependent CP violation parameters in B^0 → K_S^0 π^0 γ decays using a dataset of approximately 772 × 10^6 and 521 × 10^6 Υ(4S) decays collected by the Belle and Belle II experiments, respectively. The measured parameters for the combined dataset in the K^*0(892) dominated region (M_K_S^0 π^0 ∈ [0.8,1.0] GeV/c^2) are S = 0.09 ± 0.16 ± 0.02 and C = −0.09 ± 0.08 ± 0.04. For the non-K^*0(892) region (M_K_S^0 π^0 ∈ [1.0,1.8] GeV/c^2), the corresponding values are S = −0.32 ± 0.33 ± 0.09 and C = −0.07 ± 0.17 ± 0.08. The first quoted uncertainties are statistical, while the second ones are systematic. These results are consistent with Standard Model predictions and more precise than previous measurements.
ER  -