Research On The Generation Of Strange Hadrons In The Collision Of 54.4GeV Au+Au At The Center Of Mass System

The formation of hadrons from final-state quarks and/or gluons is called the hadronization,which is a complex non-perturbative quantum chromodynamics(QCD).Because of difficulty of non-perturbative QCD,hadronization process can not be calculated and simulated via the first principle method at the moment,and is only approximately described by the phenomenological models.The study of hadronization is closely interacted with high energy collision experiments.The rich and precise experimental data can help peoples to test the existing hadronization models and find new rule in the hadronization process.Ultra-relatively heavy-ion collisions at RHIC and LHC create the hot and dense nuclear matter,now called quark-gluon plasma(QGP),in the early collision stage.In recent years,experimental and theoretical studies at RHIC and LHC found that quark(re-)combination/coalescence is an effective mechanism of describing the hadronization of QGP.Several striking experimental observations in heavy-ion collisions such as the enhanced baryon to meson ratio in the intermediate transverse momentum range and the number of constituent quark scaling of elliptic flow of hadrons can be naturally explained in the quark combination mechanism.The rich and precise experimental data of relativistic heavy-ion collisions further improve the understandings of the detailed dynamics of quark combination process.The Beam Energy Scan program(BES)at RHIC provides the precise experimental data of hadron production in Au+Au collisions at collision energy 7.7-39 GeV in the center mass frame,which greatly prompt the study of QCD phase diagram and the study of the hadronization for hot and dense quark matter with different baryon number densities.In previous works of our group,an equal-velocity combination model of constituent quarks and antiquarks at hadronization is applied to study the experimental data of hadron production in Au+Au collisions at BES energies.In the study of the constituent quark number scaling of transverse momentum spectra of strange hadrons,the multiple correlation of anti-hadron to hadron yield ratios,it was found that the equal-velocity combination mechanism can effectively describe the experimental data of hadron production at BES energies.This paper applies an equal-velocity combination model to systematically study the production of hadrons in Au+Au collisions at(?)GeV.Using the latest experimental data of STAR collaboration on yield densities and transverse momentum spectra of identified hadrons,the model is tested from different aspects.The main content of the study includes:Applying the equal-velocity combination model to calculate the yield densities and transverse momentum spectra of KS0??????-??-and their anti-baryons at midrapidity.These calculations are compared with experimental data.It is found that the momentum spectrum of ? and that ? in central and semi-central collisions exhibit the property of constituent quark number scaling,which is a direct evidence of quark combination mechanism at hadronization.Ratios of baryon to meson such as?/?and ?/KS0 as the function of transverse momentum are studies and model results are compared with experimental data.The nuclear modification factors RCP of several strange hadrons are studied and transverse momentum and hadron species dependence of RCP are analyzed.In addition,yield densities and transverse momentum spectra of ?,K,p in different collisional centralities are predicted and left to compare with the future experimental data of STAR collaboration.