Hanbury-Brown-Twiss(HBT) correlations for charged pions in central Au+Au collisions at √SNN=2.4-7.7 GeV(corresponding to beam kinetic energies in the fixed target frame from Elab=1.23 to 30 GeV/nucleon) are calculate...Hanbury-Brown-Twiss(HBT) correlations for charged pions in central Au+Au collisions at √SNN=2.4-7.7 GeV(corresponding to beam kinetic energies in the fixed target frame from Elab=1.23 to 30 GeV/nucleon) are calculated using the ultra-relativistic quantum molecular dynamics model with different equations of state(EoSs).The effects of a phase transition at high baryon densities are clearly observed in the explored HBT parameters.The results show that the available data on the HBT radii,RO/RSand R^(2)_(O)-R^(2)_(S),in the investigated energy region favor a relatively stiff EoS at low beam energies,which then turns into a soft EoS at high collision energies consistent with astrophysical constraints on the high-density EoS of quantum chromodynamics(QCD).The specific effects of two different phase transition scenarios on RO/RSand R^(2)_(O)-R^(2)_(S)are investigated.A phase transition with a significant softening of the EoS below four times the nuclear saturation density can be excluded using HBT data.Our results highlight that the pion’s RO/RSand R^(2)_(O)-R^(2)_(S)are sensitive to the stiffness of the EoS and can be used to constrain and understand the QCD EoS in a high baryon density region.展开更多
We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized i...We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model,and finally the hadronic jets are constructed from the created hadrons.Jet properties calculated with the forward method for pp collisions at √s=7 TeV are comparable to those calculated with the usual anti-kt algorithm(backward method)in PYTHIA6.4.The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11875125,and 12075085)financial support from China Scholarship Council(Grant No.202106180053)Samson AG for funding。
文摘Hanbury-Brown-Twiss(HBT) correlations for charged pions in central Au+Au collisions at √SNN=2.4-7.7 GeV(corresponding to beam kinetic energies in the fixed target frame from Elab=1.23 to 30 GeV/nucleon) are calculated using the ultra-relativistic quantum molecular dynamics model with different equations of state(EoSs).The effects of a phase transition at high baryon densities are clearly observed in the explored HBT parameters.The results show that the available data on the HBT radii,RO/RSand R^(2)_(O)-R^(2)_(S),in the investigated energy region favor a relatively stiff EoS at low beam energies,which then turns into a soft EoS at high collision energies consistent with astrophysical constraints on the high-density EoS of quantum chromodynamics(QCD).The specific effects of two different phase transition scenarios on RO/RSand R^(2)_(O)-R^(2)_(S)are investigated.A phase transition with a significant softening of the EoS below four times the nuclear saturation density can be excluded using HBT data.Our results highlight that the pion’s RO/RSand R^(2)_(O)-R^(2)_(S)are sensitive to the stiffness of the EoS and can be used to constrain and understand the QCD EoS in a high baryon density region.
基金Supported by the National Natural Science Foundation of China(11477130,11775094)the 111 project of the foreign expert bureau of China+2 种基金the financial support from Suranaree University of Technology and the Office of the Higher Education Commission under the NRU project of Thailandthe financial support from Key Laboratory of Quark and Lepton Physics in Central China Normal University(QLPL201805)the Continuous Basic Scientific Research Project(WDJC-2019-13)
文摘We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model,and finally the hadronic jets are constructed from the created hadrons.Jet properties calculated with the forward method for pp collisions at √s=7 TeV are comparable to those calculated with the usual anti-kt algorithm(backward method)in PYTHIA6.4.The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method.
