Non-extensive statistical distributions of charmed meson production in Pb–Pb and pp(p¯) collisions

The mid-rapidity transverse momentum spectra of charmed mesons in Pb–Pb and pp(p¯) collisions are analyzed using the Tsallis–Pareto distribution derived from non-extensive statistics. We provide uniform descriptions of both small and large systems over a wide range of collision energies and hadron transverse momenta. By establishing the relationship between the event multiplicity and Tsallis parameters, we observe that there is a significant linear relationship between the thermal temperature and Tsallis qparameter in Pb–Pb collisions at sNN= 2.76 TeV and 5.02 TeV. Further, the slope of the T–(q-1) parameter plot is positively correlated with the hadron mass. In addition, charmed mesons have a higher thermal temperature than light hadrons at the same q-1, indicating that the charm flavor requires a higher temperature to reach the same degree of non-extensivity as light flavors in heavy-ion collisions. The same fit is applied to the transverse momentum spectra of charmed mesons in pp(p¯) collisions over a large energy range using the Tsallis–Pareto distribution. It is found that the thermal temperature increases with system energy, whereas the qparameter becomes saturated at the pp(p¯) limit, q-1= 0.142 ± 0.010. In addition, the results of most peripheral Pb–Pb collisions are found to approach the pp(p¯) limit, which suggests that more peripheral heavy-ion collisions are less affected by the medium and more similar to pp(p¯) collisions.