A systematic analysis of transverse momentum spectra of $J/ψ$ mesons in high energy collisions

Abstract

We aggregate the transverse momentum spectra of $J/ψ$ mesons produced in high energy gold-gold (Au-Au), deuteron-gold ($d$-Au), lead-lead (Pb-Pb), proton-lead ($p$-Pb), and proton-(anti)proton ($p$-$p(\overline{p})$) collisions measured by several collaborations at the Relativistic Heavy Ion collider (RHIC), the Tevatron Proton-Antiproton Collider, and the Large Hadron Collider (LHC). The collision energy (the center-of-mass energy) gets involved in a large range from dozens of GeV to 13 TeV (the top LHC energy). We consider two participant or contributor partons, a charm quark and an anti-charm quark, in the production of $J/ψ$. The probability density of each quark is described by means of the modified Tsallis--Pareto-type function (the TP-like function) while considering that both quarks make suitable contributions to the $J/ψ$ transverse momentum spectrum. Therefore, the convolution of two TP-like functions is applied to represent the $J/ψ$ spectrum. We adopt the mentioned convolution function to fit the experimental data and find out the trends of the power exponent, effective temperature, and of the revised index with changing the centrality, rapidity, and collision energy. Beyond that, we capture the characteristic of $J/ψ$ spectrum, which is of great significance to better understand the production mechanism of $J/ψ$ in high energy collisions.