Plots of histograms for spin period and magnetic field obtained from calculations of the theoretical model and for the observed binary pulsars (red-shaded). In theoretical calculations, we assume that the initial B-field follows a Gaussian distribution, centered at 5 × 10¹² G and ranging from 5 × 10¹⁰ G (e.g. Hartman et al. 1997) to 10¹⁴ G (e.g. Kaspi 2010). As for the initial spin period, it is assumed to be a Gaussian distribution, centered at 30 s and ranging from 0.5 s to 100 s. The different accretion rates are set from to . The theoretically evolved B-field and spin period values occurred in the left parts of the plots, which are similar to the observed distributions.