Inverse slope systematics in high-energy p+p and Au+Au reactions

We employ the Monte Carlo PYTHIA to calculate the transverse mass spectra of various hadrons and their inverse slopes T∗ at mT−m=1.5–2 GeV in p+p reactions at s=200 GeV. Due to (multiple) minijet production T∗ in general increases as a function of the hadron mass. Moreover, the T∗(m) systematics has a “discontinuity” at the charm threshold, i.e. the inverse slope of D-mesons is much higher than that of non-charmed hadrons and even of the heavier ΛC baryon. The experimental observation of this characteristic behaviour in Au+Au collisions would indicate the absence of c-quark rescattering. In contrast, the assumption of thermalized partons and hydrodynamical evolution would lead to a smoothly increasing T∗(m), without discontinuity at the charm threshold. The degree of collective transverse flow, indicated by the slope of the T∗(m) systematics, depends strongly on whether kinetic equilibrium is maintained for some time after hadronization or not.