Effect of coupled channels of the multi-channel pion-pion scattering in two-pion transitions of the ${\rm Y}$ mesons

Yu. S. Surovtsev, P. Bydžovský, T. Gutsche +3

The effect of isoscalar S-wave processes $\pi \pi \to \pi \pi ,K\overline{K},\eta \eta$ is considered in the analysis of data (from the ARGUS, CLEO, CUSB, Crystal Ball, Belle, BABAR collaborations) on…