We report a search for an axion-like particle a in B -> K(*)a decays using data collected with the Belle detector at the KEKB asymmetric-energy electron-positron collider. The search is based on a 711 fb-1 data sample collected at the Upsilon(4S) resonance energy, corresponding to a sample of 772 x 106 Upsilon(4S) events. In this study, we search for the decay of the axion-like particle into a pair of photons, a -> gamma gamma. We scan the two-photon invariant mass in the range 0.16 GeV-4.50 GeV for the K modes and 0.16 GeV-4.20 GeV for the K* modes. No significant signal is observed in any of the modes, and 90% confidence level upper limits are established on the coupling to the W boson, gaW, as a function of a mass. The limits range from 3 x 10-6 GeV-1 to 3 x 10-5 GeV-1, improving the current constraints on gaW by a factor of two over the most stringent previous experimental results.
Search for an axion-like particle in B → K(*)a(→ γγ) decays at Belle
F. Bianchi;A. Boschetti;M. Destefanis;M. Maggiora;S. Marcello;R. Mussa;S. Spataro;U. Tamponi;F. Testa;
2025-01-01
Abstract
We report a search for an axion-like particle a in B -> K(*)a decays using data collected with the Belle detector at the KEKB asymmetric-energy electron-positron collider. The search is based on a 711 fb-1 data sample collected at the Upsilon(4S) resonance energy, corresponding to a sample of 772 x 106 Upsilon(4S) events. In this study, we search for the decay of the axion-like particle into a pair of photons, a -> gamma gamma. We scan the two-photon invariant mass in the range 0.16 GeV-4.50 GeV for the K modes and 0.16 GeV-4.20 GeV for the K* modes. No significant signal is observed in any of the modes, and 90% confidence level upper limits are established on the coupling to the W boson, gaW, as a function of a mass. The limits range from 3 x 10-6 GeV-1 to 3 x 10-5 GeV-1, improving the current constraints on gaW by a factor of two over the most stringent previous experimental results.| File | Dimensione | Formato | |
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JHEP12(2025)109-1.pdf
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