The Influence Of KN Potential On The Production Of Kaon Mesons In Heavy-ion Collisions At Intermediate Energies

The nuclear equation of state(EOS)has always been a very important subject in the field of nuclear physics.Kaon produced in heavy ion collisions is a useful probe for investigating the properties of dense nuclear matter.With the help of transport model simulations,it can be used to extract the information of the equation of state of nuclear matter.At present,people have a certain understanding of the state equation of the same isotopic symmetry(The number of neutrons and protons is the same)nuclear material,which is considered to be "soft".But it is not very clear to the isotope asymmetric nuclear matter.In recent years,with the deepening of research,the EOS of the isospin asymmetric nuclear material has aroused the concern of everyone,the most important part is the density-dependent symmetry energy.The simulation of experimental data combined with transport model can be used as an effective method to extract the state equation of high density nuclear matter.In this paper,we first introduce the K-meson and the transport model used in the field of heavy ion collision at home and abroad,within the newly updated version of the ultrarelativistic quantum molecular dynamics(UrQMD)model,the effects of time step on various observations(proton and meson production and collective flow)were investigated in Au + Au collisions at intermediate energies(Elab =0.6-2.0 GeV/nucleon).It is found that the observed quantity is affected by the time step in different degrees,and its effect on the pion-related observables is more obvious to the nucleonic observables.Within the UrQMD model,the kaon-nucleon(KN)potential is further taken into account and its influence on both the yield and the directed and elliptic flows of kaon mesons produced in Au + Au collisions.The results show that the KN interaction potential makes the exclusion between the Kaon mesons(K~+ andK~0)and the nucleus,resulting in a direct flow with the reverse of the nucleus.It is found that the experimental data of flows can be better described with the consideration of the KN potential,and it is further found that the K~0/K~+ yield ratio is affected by the density dependence of the nuclear symmetry energy.The K~0/K~+ratio calculated with a soft symmetry energy is lager than that with a stiff one,and the sensitivity to the density dependence of the nuclear symmetry energy at lower beam energy becomes larger.At the low energy such as 0.8 GeV/nucleon,the K~0/K~+ratio is more sensitive to the stiffness of nuclear symmetry energy than the π~- /π~+ ratio is.With the further accurate measurement of the Kaon mesons correlation observed in the process of heavy-ion collisions and the continuous optimization of the transport models,in this energy,the kaon-related observables can be utilize to reasonable and effective constraint symmetry energy.