Speaker
Description
A multi-phase transport (AMPT) model has been able to describe a wide range of bulk observables in relativistic heavy ion collisions. However, modern parton distribution functions in nuclei are necessary for studies of pQCD observables such as heavy flavors and high-$p_T$ particles. In this talk, we will first discuss the incorporation of a modern set of parton distribution functions of the free proton and impact parameter-dependent EPS09s nuclear shadowing functions in the model[1]. We find that the minijet transverse momentum cutoff $p_0$ in the two-component initial condition model needs to be enhanced at LHC energies for AA collisions compared to that for pp collisions. In addition, we use a nuclear scaling of $p_0^{AA}=p_0^{pp}A^{q(\sqrt{s})}$ for central AA collisions, where q($\sqrt{s}$)≈1/6 at very high energies, similar to the nuclear scaling of the saturation momentum scale $Q_s$ in the saturation regime for small-x gluons. We will then show our recent generalization of $p_0^{AA}$[2], where we determine its nuclear scaling with local nuclear thickness functions from the two colliding nuclei. Together with the nuclear scaling of the Lund string fragmentation parameter that controls the effective string tension, the improved AMPT model can, for the first time, describe the centrality dependence of the hadron mean transverse momentum. As a result, the transport model can now self-consistently describe the centrality dependence and system-size dependence of the overall particle yield and mean transverse momentum of small or large collision systems.
[1] C. Zhang, L. Zheng, F. Liu, S. S. Shi, Z. W. Lin, PHYSICAL REVIEW C 99, (2019) 6, 064906
[2] C. Zhang, L. Zheng, S. S. Shi, Z. W. Lin. PHYSICAL REVIEW C 104 (2021) 1, 014908.
| What kind of work does this abstract pertain to? | Theoretical |
|---|---|
| Which experiment is this abstract related to? | ALICE |
