Determination of the $K^{+}{\bar{K}}^0$ scattering length and effective range and its relation to the $a_0^{+}(980)$ from the ${\chi }_{c1}\to {\pi }^{+}{\pi }^{-}\eta$ reaction

Hai-Peng Li, Jia-Xin Lin, Wei-Hong Liang +1

We analyze the clean cusp, seen in the $\eta \pi$ mass distribution with high precision of the ${\chi }_{c1}\to \eta {\pi }^{+}{\pi }^{-}$ reaction in the BESIII experiment, with the aim of making a precise d…