Transverse-momentum properties of multipion systems produced in high-energy collisions

The results of an investigation of the correlation between the mass ($M$) and the transverse momentum ($p_T$) of multipion systems produced in $pp$ collisions at 102 and 400 GeV/c indicate that, for fixed $M$, $p_T$ distributions are only weakly dependent on the incident energy, as well as on the charge and multiplicity of the produced system. The dependence of $〈p_T〉$ on $M$ is much stronger and is similar to that measured for discrete hadronic states.