Structures of the $f_0(980)$, $a_0(980)$ mesons and the strong coupling constants $g_{f_0 K^+ K^-}$, $g_{a_0 K^+ K^-}$ with the light-cone QCD sum rules

摘要

In this article, with the assumption of explicit isospin violation arisingfrom the $f_0(980)-a_0(980)$ mixing, we take the point of view that the scalarmesons $f_0(980)$ and $a_0(980)$ have both strange and non-strangequark-antiquark components and evaluate the strong coupling constants $g_{f_0K^+ K^-}$ and $g_{a_0 K^+ K^-}$ within the framework of the light-cone QCD sumrules approach. The large strong scalar-$KK$ couplings through both the$n\bar{n}$ and $s\bar{s}$ components $g^{\bar{n}n}_{f_0 K^+ K^-}$,$g^{\bar{s}s}_{f_0 K^+ K^-}$, $g^{\bar{n}n}_{a_0 K^+ K^-}$ and $g^{\bar{s}s}_{a_0 K^+ K^-}$will support thehadronic dressing mechanism, furthermore, in spite of the constituent structuredifferences between the $f_0(980)$ and $a_0(980)$ mesons, the strangecomponents have larger strong coupling constants with the $K^+K^-$ state thanthe corresponding non-strange ones, $g_{f_0 K^+ K^-}^{\bar{s}s}\approx\sqrt{2}g_{f_0 K^+ K^-}^{\bar{n}n}$ and $g_{a_0 K^+ K^-}^{\bar{s}s}\approx\sqrt{2} g_{a_0 K^+ K^-}^{\bar{n}n}$. From the existing controversial values,we can not reach a general consensus on the strong coupling constants $g_{f_0K^+ K^-}$, $g_{a_0 K^+ K^-}$ and the mixing angles.