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.
Adachi, I., Aggarwal, L., Ahmed, H., Ahn, Y., Aihara, H., Akopov, N., et al. (2025). Search for an axion-like particle in B → K(*)a(→ γγ) decays at Belle. JOURNAL OF HIGH ENERGY PHYSICS, 2025(12), 109-0-109-26 [10.1007/jhep12(2025)109].
Search for an axion-like particle in B → K(*)a(→ γγ) decays at Belle
Branchini, P.Membro del Collaboration Group
;Budano, A.Membro del Collaboration Group
;Bussino, S.Membro del Collaboration Group
;De Pietro, G.Membro del Collaboration Group
;Laurenza, M.Membro del Collaboration Group
;Martellini, C.Membro del Collaboration Group
;Salutari, L.Membro del Collaboration Group
;
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


