Normalized differential primary charged particle yield in INEL $pp$ collisions at $\sqrt{s}=900 $GeV, averaged in$|\eta|< 0.8$. The fit ranges are $0.15< p_T< 10$ GeV/$c$ for the modified Hagedorn function (Eq.1) and $3< p_T< 10 $GeV/$c$ for the power law (Eq.2) In the lower panels, the ratios fit over data are shown The open symbols indicate here data points which are not included in the fit Errors bars are statistical only. Indicated as shaded areas are the relative systematic data errors.