Measured correlation function of \pap pairs. Statistical (bars) and systematic (boxes) uncertainties are shown separately. The Coulomb only interaction is shown by the green band. The blue band represents the fit performed using $\rm N^3$LO \chiEFT potentials~ with elastic and \nan coupled-channel. The inclusion of annihilation channels is shown by the red band, along with the $C_{\rm{background}}(\ks)$, multiplied by the normalization constant $N_D$ obtained in the fit. The reported average $\chi^2/\rm NDF$ is evaluated in the \ks interval $[0,400]$ \MeVc and it includes correlations between the data points Lower panel: $n_\sigma$ deviation between data and model in terms of numbers of statistical standard deviations.