Within the framework of the isospin-dependent quantum molecular dynamics model,we simulate^(129)Xe+^(119)Sn collisions in an incident energy range of 20 to 190MeV/nucleon and discuss the liquid-gas phase transition wi...Within the framework of the isospin-dependent quantum molecular dynamics model,we simulate^(129)Xe+^(119)Sn collisions in an incident energy range of 20 to 190MeV/nucleon and discuss the liquid-gas phase transition with density fluctuations.For comparison,we also extract the effective Fisher parameter τ_(eff),multiplicity of intermediate-mass fragments(IMFs),and information entropy.It is found that the Fisher parameter and maximum information entropy of collisions have peak values at E_(beam)=50-80 MeV/nucleon.In addition,the maximum multiplicity of IMFs has a plateau around 70 MeV/nucleon.For higher-order density moments in a larger central region of[-5,5]^(3) fm^(3) in the collision system,a maximum plateau also appears as function of beam energy at energies exceeding 70 MeV/nucleon.These observables,which are consistent with each other,indicate a liquid-gas phase transition around 70 MeV/nucleon for the^(129)Xe+^(119)Sn system.展开更多
In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular...In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular dynamics model(ImQMD)coupled with a sequential decay model(GEMINI).Three observables were analyzed:(1)the average center-of-mass kinetic energy per nucleon<Ec.m./A>of fragments as a function of their charge number Z;(2)the average neutron number to proton number ratio(<N>/Z)of fragments with a given charge number Z as a function of their center-of-mass kinetic energy per nucleon(Ec.m./A);and(3)the average total neutron number to total proton number ratio(ΣN/ΣZ)and double ratio(DR(N/Z))of IMFs with Z=3-8 as a function of their center-of-mass kinetic energy per nucleon Ec.m./A.Our calculations revealed that the sensitivity of the isospin properties of IMFs relative to the stiffness of the symmetry energy remains even after sequential decay.By comparing the calculations ofΣN/ΣZ and DR(N/Z)with the data,it was found that the soft symmetry energy,i.e.,γ=0.5,is favored.展开更多
基金partially supported by the National Natural Science Foundation of China(Nos.11890714,11891070,12075061,and12147101)Key Research Program of the CAS(No.XDB34000000)+3 种基金China Postdoctoral Science Foundation(No.2019M661332)Postdoctoral Innovative Talent Program of China(No.BX20200098)Shanghai Natural Science Foundation(No.20ZR1404100)Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030008)。
文摘Within the framework of the isospin-dependent quantum molecular dynamics model,we simulate^(129)Xe+^(119)Sn collisions in an incident energy range of 20 to 190MeV/nucleon and discuss the liquid-gas phase transition with density fluctuations.For comparison,we also extract the effective Fisher parameter τ_(eff),multiplicity of intermediate-mass fragments(IMFs),and information entropy.It is found that the Fisher parameter and maximum information entropy of collisions have peak values at E_(beam)=50-80 MeV/nucleon.In addition,the maximum multiplicity of IMFs has a plateau around 70 MeV/nucleon.For higher-order density moments in a larger central region of[-5,5]^(3) fm^(3) in the collision system,a maximum plateau also appears as function of beam energy at energies exceeding 70 MeV/nucleon.These observables,which are consistent with each other,indicate a liquid-gas phase transition around 70 MeV/nucleon for the^(129)Xe+^(119)Sn system.
基金supported by the National Natural Science Foundation of China(Nos.11875323,11705163,11790320,11790323,and11961141003)the National Key R&D Program of China(No.2018YFA0404404)+1 种基金the Continuous Basic Scientific Research Project(Nos.WDJC-2019-13,BJ20002501)funding from the China Institute of Atomic Energy and the Leading Innovation Project of CNNC(Nos.LC192209000701 and LC202309000201)。
文摘In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular dynamics model(ImQMD)coupled with a sequential decay model(GEMINI).Three observables were analyzed:(1)the average center-of-mass kinetic energy per nucleon<Ec.m./A>of fragments as a function of their charge number Z;(2)the average neutron number to proton number ratio(<N>/Z)of fragments with a given charge number Z as a function of their center-of-mass kinetic energy per nucleon(Ec.m./A);and(3)the average total neutron number to total proton number ratio(ΣN/ΣZ)and double ratio(DR(N/Z))of IMFs with Z=3-8 as a function of their center-of-mass kinetic energy per nucleon Ec.m./A.Our calculations revealed that the sensitivity of the isospin properties of IMFs relative to the stiffness of the symmetry energy remains even after sequential decay.By comparing the calculations ofΣN/ΣZ and DR(N/Z)with the data,it was found that the soft symmetry energy,i.e.,γ=0.5,is favored.
