Analysis of the coupling constants gₐ₀ηπ₀ and gₐ₀η'π₀ with light-cone QCD sum rules

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In this article, we take the point of view that the light scalar meson a₀(980) is a conventional qq state, and calculate the coupling constants gₐ₀ηπ₀ and gₐ₀ η'π₀ with the light-cone QCD sum rules. The central value of the coupling constant gₐ₀ηπ₀ is consistent with the one extracted from the radiative decay ϕ(1020)→ a₀(980)γ→ ηπ⁰ γ. The central value and lower bound of the decay width Γₐ₀→ ηπ₀=127⁺⁸⁴₋₄₈ MeV are compatible with the experimental data of the total decay width Γₐ₀₍₉₈₀₎=(50-100) MeV from the Particle Data Group with very model dependent estimation (the decay width can be much larger), while the upper bound is too large. We give possible explanation for the discrepancy between the theoretical calculation and experimental data.