Search for the rare charm meson decays $D^0 \to h h^{\prime} e^+ e^-$

Sumitted to PubDB: 2026-03-27

Category: Physics / performance paper

Tags:

Principal Authors Shuaiyan Kang, Soeren Prell
Date 2026-03-29
Working group Charm
Belle II Number BELLE2-PUB-PH-2026-013
Abstract We present a study of the rare charm meson decays $ D^{0}\rightarrow K^{+}K^{-}e^{+}e^{-} $, $ π^{+}π^{-}e^{+}e^{-} $, and $ K^{-}π^{+}e^{+}e^{-} $ using a 942 fb$^{-1}$ data set collected by the Belle detector at the KEKB asymmetric-energy $ e^{+}e^{-} $ collider. We use $ D^{0} $ candidates identified by the charge of the pion in $ D^{*} \rightarrow D^{0} π$ decays and normalize the branching fractions to $ D^{0} \rightarrow K^{-}π^{+}π^{-}π^{+} $ decays. The branching fraction for decay $ D^{0} \rightarrow K^{-}π^{+}e^{+}e^{-} $ is measured to be (39.6 $\pm$ 4.5 (stat) $\pm$ 2.9 (syst)) $\times$ $10^{-7}$, with the dielectron mass in the $ ρ/ω$ mass region $ 675 < m_{ee} < 875 $ MeV$/c^{2}$. We also search for $ D^{0}\rightarrow h^{-} h^{(\prime)+}e^{+}e^{-} $ ($ h^{(\prime)}=K,\,π$) decays with the dielectron mass near the $η$ and $ϕ$ resonances, and away from these resonances for the $ K^{+}K^{-}e^{+}e^{-} $ and $ π^{+}π^{-}e^{+}e^{-} $ modes. For these modes, we find no significant signals and set 90$\%$ confidence level upper limits on their branching fractions at the $\mathcal{O}$(10$^{-7}$) level.
ArXiv https://arxiv.org/abs/2507.05050
Inspire https://inspirehep.net/literature/2942803
DOI 10.1103/mkx8-cl23
Reference Phys.Rev.D 112, L071101 (2025)
Bibtex 
@article{Belle:2025ltu,
    author = "Adachi, I. and others",
    collaboration = "Belle, Belle-II",
    title = "{Measurement of the D0{\textrightarrow}K-{\ensuremath{\pi}}+e+e- branching fraction and search for D0{\textrightarrow}{\ensuremath{\pi}}+{\ensuremath{\pi}}-e+e- and D0{\textrightarrow}K+K-e+e- decays at Belle}",
    eprint = "2507.05050",
    archivePrefix = "arXiv",
    primaryClass = "hep-ex",
    reportNumber = "Belle II Preprint 2025-020; KEK Preprint 2025-19",
    doi = "10.1103/mkx8-cl23",
    journal = "Phys. Rev. D",
    volume = "112",
    number = "7",
    pages = "L071101",
    year = "2025"
}

Files

-