The average transverse-momentum fraction (\meanz) for \lmb~(\almb) (blue) and \kzero (red) as a function of \pts in minimum bias \pp collisions at \thirteen. The \pts ranges from 0.6 to 20 \GeVc Statistical and systematic uncertainties of \meanz are represented by vertical error bars and empty boxes, respectively Data points are drawn at the corresponding average \pts values in each interval The horizontal bars represent the \pts interval widths The statistical and systematic uncertainties of the average \pts values are negligible.