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.