Search for the decay $B^{0} \to \gamma \gamma$ using Belle and Belle II data

Abstract We report the result of a search for the rare decay $B^{0} \to \gamma \gamma$ using a combined dataset of $753\times10^{6}$$B\bar{B}$ pairs collected by the Belle experiment and $387\times10^{6}$$B\bar{B}$ pairs collected by the Belle II experiment from decays of the $\rm \Upsilon(4S)$ resonance produced in $e^{+}e^{-}$ collisions. A simultaneous fit to the Belle and Belle II data sets yields $11.0^{+6.5}_{-5.5}$ signal events, corresponding to a 2.5$\sigma$ significance. We determine the branching fraction $\mathcal{B}(B^{0} \to \gamma\gamma) = (3.7^{+2.2}_{-1.8}(\rm stat)\pm0.5(\rm syst))\times10^{-8}$ and set a 90% credibility level upper limit of $\mathcal{B}(B^{0} \to \gamma\gamma) < 6.4\times10^{-8}$.
Tags
Working group Radiative and Electroweak Penguin
Principal authors @  Bipul Bhuyan, Dibyajyoti Kalita, Shubhangi Maurya
Reference Phys.Rev.D 110, L031106 (2024), DOI: 10.1103/PhysRevD.110.L031106
Document BELLE2-PUB-PH-2024-053
Links arXiv:2405.19734, Inspire, PRD
Bibtex 
@article{Belle:2024bsw,
    author = "Adachi, I. and others",
    collaboration = "Belle, Belle-II",
    title = "{Search for the decay B0{\textrightarrow}{\ensuremath{\gamma}}{\ensuremath{\gamma}} using Belle and Belle II data}",
    eprint = "2405.19734",
    archivePrefix = "arXiv",
    primaryClass = "hep-ex",
    reportNumber = "Belle II Preprint: 2024-017, KEK Preprint: 2024-13",
    doi = "10.1103/PhysRevD.110.L031106",
    journal = "Phys. Rev. D",
    volume = "110",
    number = "3",
    pages = "L031106",
    year = "2024"
}