Production of leptons from decay of heavy-flavor hadrons in high-energy nuclear collisions

This paper presents a theoretical study on the production of leptons from decay of heavy-flavor hadrons (denoted as HFLs) in high-energy nuclear collisions at the CERN Large Hadron Collider. The pp baseline is calculated by the fonll program, which matches the next-to-leading order perturbative QCD (pQCD) calculation with the next-to-leading-logarithm large-p(T) resummation. The in-medium propagation of heavy quarks is driven by the modified Langevin equations, which consider both the elastic and inelastic partonic interactions. We propose a method to separate the respective influence of the six factors, i.e., pp spectra, cold nuclear matter (CNM) effects, in-medium energy loss (E-loss), fragmentation functions (FFs), coalescence (Coal), and decay channels, which may contribute to the larger R-AA of HFL <- b compared to that of HFL <- c in nucleus-nucleus collisions. Based on quantitative analysis, we demonstrate that both coalescence hadronization decay channels and the mass-dependent E-loss play an essential role at p(T) <5GeV, while the latter dominates the higher P-T region. It is also found that the influences of the CNM effects and FFs are insignificant. At the same time, different initial pp spectra of charm and bottom quarks have a considerable impact at p(T)>5GeV. Furthermore, we explore the path-length dependence of jet quenching by comparing the HFL R-AA in two different collision systems. Our investigations show smaller HFL R-AA in Pb+Pb than in Xe+Xe within the same centrality bin, consistent with the ALICE data. The longer propagation time and more effective energy loss of heavy quarks in Pb+Pb collisions play critical roles in the stronger yield suppression of the HFLs compared to that in Xe+Xe. In addition, we observe a scaling behavior of the HFL R-AA in Xe+Xe and Pb+Pb collisions.