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

Abstract

In this article, with the assumption of explicit isospin violation arising from the $f_0(980)-a_0(980)$ mixing, we take the point of view that the scalar mesons $f_0(980)$ and $a_0(980)$ have both strange and non-strange quark-antiquark components and evaluate the strong coupling constants $g_{f_0{K}^{+}{K}^{-}}$ and $g_{a_0{K}^{+}{K}^{-}}$ within the framework of the light-cone QCD sum rules approach. The large strong scalar-$KK$ couplings through both the $n\bar{n}$ and $s\bar{s}$ components $g_{f_0{K}^{+}{K}^{-}}^{\bar{n}n}$, $g_{f_0{K}^{+}{K}^{-}}^{\bar{s}s}$, $g_{a_0{K}^{+}{K}^{-}}^{\bar{n}n}$ and $g_{a_0{K}^{+}{K}^{-}}^{\bar{s}s}$will support the hadronic dressing mechanism, furthermore, in spite of the constituent structure differences between the $f_0(980)$ and $a_0(980)$ mesons, the strange components have larger strong coupling constants with the $K^{+}{K}^{-}$ state than the 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 $g_{f_0{K}^{+}{K}^{-}}$, $g_{a_0{K}^{+}{K}^{-}}$ and the mixing angles.

Comments: 14 pages; Revised version