Ratio of the simulated non-prompt D$^0$ distribution in the detector (detector-level) over the efficiency-corrected data, which includes contributions from the prompt and feed-down D$^0$. The non-prompt D$^0$ fraction is shown for $\Delta R_{\rm STD-D^0}$ and $\Delta R_{\rm SD-D^0}$ ($z_{\rm cut}=0.1,0.2$ and $\beta=0$). Systematic and statistical uncertainties are represented by the corresponding color boxes and error bars, respectively.