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

Abstract

In this article, we take the point of view that the light scalar meson a0(980) is a conventional qq̄ state, and calculate the coupling constants ga0ηπ0 and ga0η′π0 with the light-cone QCD sum rules. The central value of the coupling constant ga0ηπ0 is consistent with that extracted from the radiative decay ϕ(1020) → a0(980)γ → ηπ0γ. The central value and lower bound of the decay width Γa0→ηπ0 = 127−48+84 MeV are compatible with the experimental data of the total decay width Γa0(980) = (50–100) MeV from the Particle Data Group with a very model dependent estimation (the decay width can be much larger), while the upper bound is too large. We give a possible explanation for the discrepancy between the theoretical calculation and experimental data.