Width of (a) $\RtwoCI(\Deta)$ (blue markers) and $\PtwoCI(\Deta)$ (red markers) and (b) $\RtwoCD(\Deta)$ (blue markers) and $\PtwoCD(\Deta)$ (red markers) correlation functions along $\Deta$ measured within $|\Dphi| \pi$ in pp collisions and compared with results from p--Pb and Pb--Pb collisions  as a function of $\dnavg$. Vertical bars and boxes represent statistical and systematic uncertainties, respectively.