Light scalar mesons and two-kaon correlation functions

It is shown that the recent data on the $K_S^0{K}^{+}$ correlation in Pb-Pb interactions agree with the data on the $\gamma \gamma \to \eta {\pi }^0$ and $\varphi \to \eta {\pi }^0\gamma$ reactions and support the four-quark model of the $a_0(980)$ meson. It is shown that the data does not contradict the validity of the Gaussian assumption. The study of two-kaon correlations could provide more information about light scalar mesons after increasing the accuracy of the experimental and theoretical descriptions.

Figure 1

(a) The $\gamma \gamma \to \eta {\pi }^0$ cross section: the curve is Fit 1, and the data points are from Belle [37]. Note that the Belle data represent the averaged cross section (each bin is 20 MeV). (b) Plot of the Fit 1 curve and the KLOE data (points) [13] on the $\varphi \to \eta {\pi }^0\gamma$ decay; $m$ is the invariant $\eta {\pi }^0$ mass. Cross points are omitted in the fitting.

Figure 2

$K_S^0{K}^{+}$ correlation: the solid line corresponds to Fit 1, and the points are experimental data [24].