Ω and ϕ production in Au + Au collisions at 
                
                  
                
                $$\sqrt{s_{_\mathrm{NN}}} = 11.5$$
                
                  
                    
                      
                        
                          s
                          
                            
                            NN
                          
                        
                      
                      =
                      11.5

Self Cite

Cascade solutions of the Boltzmann equation suffer from causality violation at high densities and/or scattering cross sections. Although the particle subdivision technique can reduce the causality violation, it alters event-byevent correlations and fluctuations and is also computationally expensive. Here we evaluate and then improve the accuracy of the ZPC parton cascade for elastic scatterings inside a box without using parton subdivision. We first test different collision schemes for the collision times and ordering time and find that the default collision scheme does not accurately describe the equilibrium momentum distribution at large opacities. We then find a specific collision scheme that can describe very accurately the equilibrium momentum distribution as well as the time evolution towards equilibrium, even at large opacities. We also calculate the shear viscosity and the η/s ratio of the parton systems and confirm that the new collision scheme is more accurate. In addition, we use a novel parton subdivision method to obtain the "exact" evolution of the system. This subdivision method is valid for such box calculations and is so much more efficient than the standard subdivision method that we use a subdivision factor of 10 6 in this study.

Section: Introductionmentioning

confidence: 99%

Validation and improvement of the ZPC parton cascade inside a box

Zhao

et al. 2020

Self Cite

“…Partonic matter is then turned into hadronic matter and the subsequential hadronic interactions are simulated using a relativistic transport model (ART) including both elastic and inelastic scattering descriptions for baryon-baryon, baryon-meson, and meson-meson interactions [57]. With properly choosing partonic scattering cross section, the AMPT model was successful in describing many experimental observations in heavy-ion collisions at RHIC and LHC energies [58][59][60][61].…”

Section: Model and Methodsmentioning

confidence: 99%

Anisotropy fluctuation and correlation in central α -clustered C12+Au197 collisions

Song

2020

In the framework of a multiphase transport model, fluctuation and correlation of the azimuthal anisotropies in 12 C + 197 Au collisions at √ S NN = 200 GeV are explored. Properties of the initial eccentricity and final harmonic flow fluctuation resulted from 12 C + 197 Au collisions with Woods-Saxon configuration and triangular α-clustering configurations of 12 C are investigated via scaled variance, skewness, and kurtosis. Comparisons are made between results from α-clustered configurations and Woods-Saxon configuration. The triangular flow fluctuation is found to have particular sensitivity in distinguishing triangular α-clustering structure of 12 C. Furthermore, correlations between initial eccentricities and final flow harmonics are studied with strong multiplicity dependence observed for the correlation functions.

“…With the refinement of the quark coalescence algorithm for hadronization, the AMPT model has further improved its description of the experimental data, especially the baryon p T spectra and the antibaryon over baryon ratios [29]. On the other hand, all versions of the AMPT model, including the recent AMPT model with the new quark coalescence algorithm (v1.31t1/2.31t1) [29], have problems in reproducing the yields and p T spectra of multistrange baryons in heavy-ion collisions [29][30][31][32]. For example, the − yield from the default AMPT model [30] is a factor of two smaller than the Pb + Pb data measured at the SPS energy of 158 AGeV.…”

Section: Ampt Modelmentioning

confidence: 99%

Enhanced production of strange baryons in high-energy nuclear collisions from a multiphase transport model

Shao

Chen

et al. 2020

We introduce additional coalescence factors for the production of strange baryons in a multiphase transport (AMPT) model in order to describe the enhanced production of multistrange hadrons observed in Pb + Pb collisions at √ s NN = 2.76 TeV at the Large Hadron Collider (LHC) and Au + Au collisions at √ s NN = 200 GeV at Relativistic Heavy-Ion Collider (RHIC). This extended AMPT model is found to also give a reasonable description of the multiplicity dependence of the strangeness enhancement observed in high multiplicity events in pp collisions at √ s = 7 TeV and p-Pb collisions at √ s NN = 5.02 TeV. We find that the coalescence factors depend on the system size but not much on whether the system is produced from A + A or p + A collisions.The extended AMPT model thus provides a convenient way to model the mechanism underlying the observed strangeness enhancement in collisions of both small and large systems at RHIC and LHC energies.