Using local nuclear scaling of initial condition parameters to improve the system size dependence of transport model descriptions of nuclear collisions

Authors：Zhang, Chao; Zheng, Liang; Shi, Shusu; Lin, Zi-Wei^*

Source：Physical Review C - Nuclear Physics, 2021, 104(1): 014908.

DOI：10.1103/PhysRevC.104.014908

• TRANSVERSE-MOMENTUM DISTRIBUTIONS
• PROTON-PROTON COLLISIONS
• PB-PB COLLISIONS
• XE-XE COLLISIONS
• SQUARE-ROOT-S
• CHARGED-PARTICLES
• PSEUDORAPIDITY DISTRIBUTIONS
• CENTRALITY DEPENDENCE
• PP COLLISIONS
• FLOW

We extensively study the system size dependence of nuclear collisions with a multiphase transport model. Previously, certain key parameters for the initial condition needed significantly different values for pp and central AA collisions for the model to reasonably describe the yields and transverse momentum spectra of the bulk matter in those collision systems. Here we scale two key parameters, the Lund string fragmentation parameter b(L) and the minij et transverse momentum cutoff p(0), with local nuclear thickness functions from the two colliding nuclei. This allows the model to use the parameter values for pp collisions with the local nuclear scaling to describe the system size and centrality dependences of nuclear collisions self-consistently. In addition to providing good descriptions of pp collisions from 23.6 GeV to 13 TeV and reasonable descriptions of the centrality dependence of charged particle yields for Au+Au collisions from 7.7A GeV to 200A GeV and Pb+Pb collisions at Large Hadron Collider energies, the improved model can now well describe the centrality dependence of the mean transverse momentum of charged particles below p(1) < 2 GeV. It works similarly well for smaller systems including pPb, Cu+Cu and Xe+Xe collisions.