Search for rare $b \to d \ell^+\ell^{\mathstrut -}$ transitions at Belle

Abstract We present the results of a search for the $b \to d\ell^+\ell^-$ flavor-changing neutral-current rare decays $B^{+, 0} \to (\eta, \omega, \pi^{+,0}, \rho^{+, 0}) e^+e^-$ and $B^{+, 0} \to (\eta, \omega, \pi^{0}, \rho^{+}) \mu^+\mu^-$ using a $711$ fb$^{-1}$ data sample that contains $772 \times 10^{6}$$B\overline{B}$ events. The data were collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We find no evidence for signal and set upper limits on branching fractions at the $90\%$ confidence level in the range $(3.8 - 47) \times 10^{-8}$ depending on the decay channel. The obtained limits are the world's best results. This is the first search for the channels $B^{+, 0} \to (\omega, \rho^{+,0}) e^+e^-$ and $B^{+, 0} \to (\omega, \rho^{+})\mu^+\mu^-$.
Tags
Working group Radiative and Electroweak Penguin
Principal authors @  Chunhui Chen, Seema Choudhury, James Cochran, Soeren Prell
Reference Phys.Rev.Lett. 133, 101804 (2024), DOI: 10.1103/PhysRevLett.133.101804
Document BELLE2-PUB-PH-2023-004
Links arXiv:2404.08133, Inspire, PRL
Bibtex 
@article{Belle:2024cis,
    author = "Adachi, I. and others",
    collaboration = "Belle, Belle-II",
    title = "{Search for Rare b{\textrightarrow}d{\ensuremath{\ell}}+{\ensuremath{\ell}}- Transitions at Belle}",
    eprint = "2404.08133",
    archivePrefix = "arXiv",
    primaryClass = "hep-ex",
    reportNumber = "Belle II Preprint 2024-005, KEK Preprint 2023-52",
    doi = "10.1103/PhysRevLett.133.101804",
    journal = "Phys. Rev. Lett.",
    volume = "133",
    number = "10",
    pages = "101804",
    year = "2024"
}