Measured correlation function of \psiZCombCF. Statistical (bars) and systematic uncertainties (boxes) are shown separately. The gray band denotes the \pSBCF baseline. The data are compared with different theoretical models. The corresponding correlation functions are computed using CATS  for \chiEFT , \NSC  and \ESC , and using the \Ledn  for \fss . The width of the bands corresponds to one standard deviation of the systematic uncertainty of the fit. The absolute correlated uncertainty due to the modeling of the \pSBCF baseline is shown separately as the hatched area at the bottom of the figure.