Intriguing similarities between high-$p_{\rm T}$ particle production in pp and A-A collisions

Abstract

In this paper we study the particle production at high transverse momentum ($p_{\rm T}>8$ GeV/$c$) in both pp and Pb-Pb collisions at LHC energies. The characterization of the spectra is done using a power-law function and the resulting power-law exponent ($n$) is studied as a function of $x_{\rm T}$ for minimum-bias pp collisions at different $\sqrt{s}$. The functional form of $n$ as a function of $x_{\rm T}$ exhibits an approximate universal behavior. PYTHIA~8.212 reproduces the scaling properties and therefore, it is used to study the multiplicity-dependent particle production. Going from low to high multiplicities, the power-law exponent decreases. A similar behavior is also observed in heavy-ion collisions when one studies the centrality-dependent particle production. The interpretation of heavy-ion results requires the quantification of the impact of this correlation (multiplicity and high $p_{\rm T}$) on jet-quenching observables.