Analysis of the coupling constants $g_{a_0\eta\pi^0}$ and $g_{a_0\eta'\pi^0}$ with light-cone QCD sum rules

TL;DR

This paper calculates the coupling constants of the scalar meson a0(980) with eta and pi0 mesons using light-cone QCD sum rules, providing results consistent with some experimental data and discussing discrepancies.

Contribution

It introduces a calculation of the a0(980) coupling constants assuming a q̄q structure, using light-cone QCD sum rules, and compares results with experimental data.

Findings

The calculated g_{a_0ηπ^0} aligns with decay data.

The decay width estimate is compatible with experimental bounds.

Discrepancies between theory and experiment are discussed.

Abstract

In this article, we take the point of view that the light scalar meson $a_0(980)$ is a conventional $q\bar{q}$ state, and calculate the coupling constants $g_{a_0\eta\pi^0}$ and $g_{a_0 \eta'\pi^0}$ with the light-cone QCD sum rules. The central value of the coupling constant $g_{a_0\eta\pi^0}$ is consistent with the one extracted from the radiative decay $\phi(1020)\to a_0(980)\gamma \to \eta \pi^0 \gamma$. The central value and lower bound of the decay width $\Gamma_{a_{0}\to \eta \pi^0}=127^{+84}_{-48} \rm{MeV} $ are compatible with the experimental data of the total decay width $\Gamma_{a_0(980)}=(50-100) \rm{MeV}$ 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.