Evolution of the ratio of $\sqrt{ \langle\langle \Delta p_{\rm T1}\Delta p_{\rm T2} \rangle\rangle }/{\langle\langle p_{\rm T} \rangle\rangle }$ to results of a power-law fit to HIJING calculations: (left) pp and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV; (right) pp collisions at $\sqrt{s_{\rm NN}} =5.02$ TeV and Xe$-$Xe collisions at $\sqrt{s_{\rm NN}} =5.44$ TeV. The power-law fit was performed on correlator values obtained with HIJING for Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV and Xe$-$Xe collisions at $\sqrt{s_{\rm NN}} = 5.44$ TeV for left and right panel, respectively, as described in the text. Solid symbols represent the measured data reported in this work with statistical (vertical bars) and systematic (boxes) uncertainties. Calculations of the ratios obtained with HIJING and AMPT calculations are shown with shaded bands denoting their statistical uncertainty.