Search for ALP through B→Ka'(a'→γγ) decay at Belle

Abstract We report research on Axion-Like-Particle(ALP) through B → K a'(a' → γγ) channel. in this research, we are looking for ALP which decay into a pair of photons. Without expectation of the ALP mass, we scan the kinematically allowed mass region of the ALP by dividing the search region into small windows from 0.16 GeV/c^2 to 4.50 GeV/c^2 (K+ , K_S0 modes) or 4.2 GeV/c 2 (K∗0 , K∗+ mode). We use the Belle experiment Monte-Carlo (MC) simulation sample to obtain the expected upper limit of BF(B → Ka') for each ALP mass scan point.the 90% confidence level upper limits on ga′ W coupling for each ALP mass hypothesis are established as function of the ALP mass. The result improve current constraint on ga′ W .
Tags Belle
Working group Dark Sector and Low Multiplicity
Principal authors @  Sungjin Cho, Youngjoon Kwon
Reference JHEP 12, 109 (2025), DOI: 10.1007/JHEP12(2025)109
Links arXiv:2507.01249, Inspire, JHEP
Bibtex 
@article{Belle:2025zbq,
    author = "Adachi, I. and others",
    collaboration = "Belle, Belle-II",
    title = "{Search for an Axion-Like Particle in $B\rightarrow K^{(*)} a (\rightarrowγγ)$ Decays at Belle}",
    eprint = "2507.01249",
    archivePrefix = "arXiv",
    primaryClass = "hep-ex",
    reportNumber = "Belle II Preprint: 2025-017 KEK Preprint: 2025-16",
    doi = "10.1007/JHEP12(2025)109",
    journal = "JHEP",
    volume = "12",
    pages = "109",
    year = "2025"
}